Answering that question: How do I turbocharge my S10?

[Injected]

I've been requested to expand on the idea of compressor maps and selection. The reason I decided to put this in its own thread was because I’ve done this before, (maybe not to this extent) and from now on I’ll just reference or add onto this.

Understanding compressor maps is relatively easy. Using one takes a little math, but that too takes only the skill of a middle school student.

The compressor map itself is a representation of the efficiency of the compressor as expressed as a correlation between the pressure ratio (y-axis) and airflow (x-axis) properties.

The first thing you need to do is to make a plan and know exactly what you want from your compressor. I cannot stress this enough. What characteristics do you want your engine to have? Be realistic, you can’t have it all (at least not yet). You should decide what part of the rev range you want to prop up the most with your compressor, and whether that compressor is found in a supercharger or turbo charger, which is a whole other thread. You should decide what compression ratio you want to use to best utilize your desired characteristics, available fuel and desired boost level.

Once you have decided what the characteristics of your system should be, you can begin selecting the compressor for your forced induction system.

Since you’ve decided what boost level you want to run when you looked at the octane rating at the local pump, decided what kind of fuel management system you will run and selected a compression ratio to match, you can figure out what the pressure ratio of your system is. Pressure ratio is the expression of pressure relative to atmospheric pressure at sea level (~14.7psi) and is more commonly known as “boost” and measured in psi here in the states. We need to find the total pressure ratio at the compressor outlet needed to support our desired boost level. Air at sea level is already at 14.7 psi, so that, plus what we want to add (boost desired), plus intercooler pressure drop (if applicable). At this point I realize that we need an example. How about a turbocharged 4.3L engine (Sy/Ty anyone?). Okay, say we’re going for a boost level of about 15psi and will run a front mount intercooler with a pressure drop of 1.5 psi. That means the pressure at the compressor outlet will need to be: 14.7psi + 15psi + 1.5psi = 31.2psi.
31.2psi expressed as a ratio of atmospheres is just 31.2psi divided by the original atmospheric pressure, in this case 14.7psi, so: 31.2psi/14.7psi = 2.12. And now we have our Y-axis value. Yay.

Now things get a bit more complicated. We need to know the flow requirements of our system.

To do that, we need to know what the intake temperature of the air is since cooler air is more dense and thus there is actually more air per given volume. Most people just make an assumption, but it can be very different for different boost levels, compressors and intercooler combinations. This is also where it is a good idea to have a compressor in mind or at least note that compressors have efficiencies typically ranging from 72-78%. We’ll pick a happy 76%. If we want to select a specific compressor then recalculate it using the compressor specific numbers, that would be ideal. Why does it make a difference? Because I said so…and also because the percentage coincidently happens to represent the amount of work that the compressor uses to achieve an increase in pressure. The rest goes toward generating heat, a crappy byproduct due to that one pesky law of physics when compressing gasses. Intercoolers also have an efficiency rating very similar to this, but an intercooler is a reverse engine. Look it up, figure it out.
To actually calculate the intake temperature, we do this:

temp out = temp in + (temp in * (-1+(pressure out/pressure in)^.263))/efficiency.

Temp in is the compressor inlet temperature in Rankin. To get Rankin, add 460 to the temperature in Fahrenheit. Compressor inlet temperature can vary due to placement of the filter and other things. We’ll assume the filter is relocated to pull in fresh air from outside and is at ambient, which we say is 80°F. Also, pressure in is absolute, but we must also consider that pulling air through a cotton gauze filter creates a slight vacuum in the intake tract before the compressor, so the 14.7psi actually goes to 14psi. We need to include our pressure drop as well as this pressure must be achieved by the compressor.

So our compressor outlet temperature is:
(80°F + 460) + ((80°F + 460)*(-1 + ((14psi + 15psi + 1.5psi)/(14psi)))^.263)/.76 =
540 + (540* (-1 + (2.18)^.263))/.76 = 701.6

Subtract to get back to Fahrenheit: 241.6°F

That’s pretty damn hot! That’s why intercoolers are great. If you are not running an intercooler, then that is your actual intake temperature, and you shouldn’t have added in intercooler pressure drop to that calculation (duh!). If you are running a good front mounted unit, like we supposedly are, then you need to figure out what your post intercooler temperature is, which is calculated by taking the intercooler inlet temperature and subtracting the heat taken out by it, which is intercooler efficiency times the difference between the inlet temperature and the ambient temperature:

241.6°F – (.83(241.6°F-80°F)) = 107.5°F.

Still with me? So now we just need to calculate the density of the intake air and how much of it is being flowed. That will give us our X value. The density of the air can be found using this formula:

(boost + atmosphere)/(R*12*intake temperature).

R is a constant from the ideal gas law. Just know it’s 53.3 and intake temperature is in Rankin.

Di = (15psi + 14.7psi)/(53.3*12*(460 + 107.5°F) = .00008182 lb/in^3.

We need to figure out what the mass flow of the engine at our desired rpm, which will be the stock 4400rpm. The mass flow rate (Mf) is calculated by using this formula:

(Di*displacement*(rpm/2)*VE).

Di is from our last calculation, displacement is in cubic inches and VE stands for volumetric efficiency. I’m going to put in 85% for VE. If you disagree with this…whatever, you run this show.

So Mf = .00008182 lb/in^3 * 262 in^3 * (2200) * .85 = 40.1 lb/min.

Now we just calculate the corrected mass flow which is: Mf * ((compressor inlet temperature/(460 + ambient temperature))^.5) / (atmosphere/compressor inlet pressure). Plug it in to get: CMf = 40.1 lb/min * ((550/550)^.5)/(14.7psi/14psi) = 38.1 lb/min.

There’s your X axis value, and now you have the two values needed to plot at least the maximum point on the compressor map.

Well, it's about 3AM here and I think that’s enough for now. I realized while writing this that the Syclone engines came with a Mitsubishi TD06-17C 8 cm² turbo.

In my next post, I’ll talk about the properties of the turbochargers and superchargers when looking at these maps and how to select a good charger for your application. Some day soon maybe.

[Rinkrat456]

Seems like a simple math problem that would combine all the year's teachings into a final test. But anywho, thanks for clearing that up. I'm already subsribed to the follow-up post.

[Injected]

Since we are talking about compressors and thus either centrifugal type superchargers (CTS) or turbochargers (TC), and we have reached the point where we can start to look at compressor maps and determine which ones will best suit our needs, we need to discuss the differences between the two in relation to boost production.

A CTS will only reach its maximum boost once, and its boost will increase with the square of the ratio of the engine speed. What that means is that if we went with a CTS for our 4.3 and wanted to run 10psi, we would see 10psi only at 4400rpm. At 2200 we would see only 2.25psi of boost (here’s the calculation: 10psi*(2200rpm/4400rpm)^2). That’s not horrible, but it’s not good either, not to mention the strain (read: parasitic loss) that 15psi system will have in contrast to a mere 8psi setup. This is why many CTS nay-sayers will tell you that the CTS combines both the downsides of both superchargers and turbochargers.

In order to overlay our desired CTS properties on the compressor map to see if it is a good match, we need to calculate the PR and CFM at maybe three or four different points in order to see if you have a good match. If you fed all of the formulas into an Excel spreadsheet or the likes, then this will be very easy. I’m going to change the parameters of the theoretical engine in order to better accommodate available compressors for this application. Let’s start with a Vortech A-Trim supercharger running 10psi. We’ll plot four points (I hope you all understand the amount of calculations I have to do just to prove a point) on the map. One at 1100, 2200, 3300, and 4400rpm. Remember, each calculation needs to use the compressor efficiency that the point will eventually land on, so some trial and error may be needed.

For the A-trim supercharger, we get these values:

1100rpm: .625psi; PR= 1.14; CMf=5.07
2200rpm: 2.5psi; PR= 1.272; CMf= 11.28
3300rpm: 5.625psi; PR= 1.485; CMf = 19.41
4400rpm: 10psi; PR= 1.782; CMf= 30.11

Plot these values on this map:
http://www.rbracing-rsr.com/turbo/TurboMaps/vortech_a_trim_map.gif

You’ll notice that the values run very high and steep on the left side of the optimal zone for this turbo as well as exceed 40K rpm. That means that this compressor is better suited for lower pressures and higher flowing engines (meaning probably about 8psi on a small block V8)

In truth, I could not find even a good match for the 4.3L from Vortech.

At some point I’ll look at that turbocharger setup I mentioned in the first post.

[Rob]

Looks like I jumped a head getting my A-Trim. That's alright, once I get everything done, I will upgrade my compressor.

[Injected]

This question gets asked a lot. So here’s the answer (or at least the beginning of the answer). And no, this is not a project, but no one does it so it may as well be discusses as if someone was to want to undertake such a project. Nobody makes a turbo kit for the S-10 series anymore. There once was a company that did for the 2.2L guys, but they didn’t last for long. As for the 4.3L guys, well you can always try and get the parts from the dealer and a dealer manual and recreate the same setup. Either way, the steps in creating a custom kit are the same.

If you are undertaking this as a project, then I suppose that you have some fairly decent mechanical skills and also know when to go for professional help. If you can’t tell when you’re getting over your head, this is not the project for you. If you cannot manage projects or do not finish other things that you start, this is not the project for you. If you cannot afford to do this right, then this is not the project for you. If you cannot afford the downtime, this is not the project for you. You’ll end up with a half finished project, a pile of parts and bills, and a lot of frustration.

The first thing to consider is which engine you are going to strap the turbo to. The 2.2L guys are going to have it far easier due to the good amount of real-estate found under the hood. The problem with the 2.2 is that the bottom end isn’t so very strong and a few people question how long the transmission will hold up. The answer is simple, create a safe turbo setup with zero knock/detonation and see how long your transmission holds up. Personally, I believe the transmission issue depends on a lot of different factors, but mostly driving habits. If you don’t drag-launch from light to light, slamming all the gears, plus given more than regular maintenance, your transmission should last for a while. If not, then modify the transmission.

Once you have decided that you have to have a turbocharger for that engine under the hood of you dime, you need to choose one. I’m not going to go over this one again because it’s rather involved and I already have several times. HERE is a link to the thread about selecting a turbo. All I’m going to say beyond this is if you (and I mean YOU) didn’t come to the conclusion that the turbo you are buying is THE turbo for YOUR intended application, then you didn’t do your homework and are likely going to end up with a turbo that either lags or falls on it’s face. Sure you might get decent numbers, but you may only be living up to half of the performance you could have gotten from a different turbo.

Okay, besides the turbo, you will need to again consider the application and decide what additional parts you will need to gather. Are you going to run high enough boost to need a compressor bypass valve? Will the intake temperature necessitate an intercooler? A boost controller, either manual or electronic, will be needed for a turbo as waste-gate actuators will not be good enough, especially if you are planning to run higher levels of boost and also considering that some turbine housings don’t have internal waste-gates. Then there’s piping. You will need both intake pipes and an exhaust manifold to bolt the turbo to. One at a time though.

Compressor bypass valve: If you are going to run more than 6 psi, then when the throttle plate closes under boost (i.e. shifting or throttle release) the slamming of air charge into the throttle plate will cause a sudden back up of pressure, and the sudden increase in pressure can damage the turbo. To counter this, a valve is put between the compressor and throttle body that will open under pressure. If you are going to run a compressor bypass valve, get one that works off of pressure differentiation (also known as a ‘pull-type’ valve) and not one that uses a simple diaphragm or spring to actuate because they tend to leak either under boost, idle or both.

Waste-gate: A waste-gate is kind of like a compressor bypass valve, except is works on the turbine instead, allowing exhaust to be diverted around the turbine. This is what allows a turbo to maintain a specific level of boost over a wide rpm range. Without one, a turbo will continue to spool faster and faster until it destroys itself. There are two different kinds of waste-gates: internal and external. An internal waste-gate is integrated into the turbine housing, whereas an external waste-gate is usually mounted to the exhaust manifold.

Intercooler: This is a big deal, pay attention. When you compress air, it gets hot…real hot. It needs to be cooled or the heat can cause detonation. Let me put it this way: a decent compressor, compressing an air charge only a little bit (7psi), will turn 85°F air into 180°F air immediately. I’m a HUGE advocate of cooling off the compressed air so that it doesn’t create hot spots and cause detonation, which will destroy an engine faster than you can say, “piston-ring-blow-by.” A good air-to-air intercooler can drop an intake charge 100°F on a mid level boost application. So how big of an intercooler should you run? Well that answer is simple. You want surface area. An air to air intercooler achieves most of its cooling capacity within the first 2.5”, so going with a 3.5” intercooler won’t really do much more than a 3” core. I suggest 3” thick at most for a street application. But as for height and width, go with what can stuff into the nose of your vehicle.

Since we are on the topic of compressed air getting hotter, let’s mention compression ratios. I expect that if you are at the point where you are considering forced induction, then you already understand the correlation between boost and compression ratios. With the air already being a bit warmer going into the cylinder, lower compression ratios will help in preventing detonation. High boost, high octane, and high compression ratios can produce amazing amounts of power, but the use of street-level octane fuel necessitates lowering the compression ratio for a far larger tuning margin when running healthy levels of boost (mid to high).

Intake piping: Your charge pipes (those between the compressor and throttle body) should all be bead rolled to prevent them from popping off. You should use multi-ply silicone connectors and T-bolt clamps to connect them. All pipes should be mandrel bent.

Exhaust piping: Believe it or not, the ricers are on to something with those huge exhausts. Reducing the back pressure on a turbo is vital to making good power. Backpressure is the enemy of any turbocharger and the best exhaust is no exhaust at all. That isn’t usually feasible, so go with the largest mandrel bent exhaust you can and use a high flow, non-baffled catalytic converter.

Lines: You’re going to need a way to get coolant and oil to the turbo, depending if your turbo water or oil cooled. I suggest using oil directly after the filter, but you will need to monitor your engines oil pressure to make sure that it is still getting enough pressure and also make sure that your turbo isn’t seeing too much pressure, which can cause damage to the center section. You can put a restrictor in line in order to achieve this. For clarification, this doesn’t mean that the oil goes through the turbo and then to the engine, but rather the two systems are separate and are pressurized by the oil pump. You’ll probably have to tap the oil pan for a return line, which may require having a bung welded in.

Fuel: We’ll this is where I leave you. There are so many ways to get more fuel into the cylinder (well, maybe not too many), that you will have to decide exactly how you want to do this. Of course the best (and that means most expensive) would be a standalone fuel management system. Whatever you decide, do a lot of research to ensure that you aren’t buying some crappy “magic chip” and that you will be able to both monitor and control the fuel entering the cylinder. I would suggest at least an EGT and fuel pressure gauge. If you can spring for a wideband 02, I suggest that in addition to or instead of the EGT gauge (really you only need one, but the wideband is better).

If any of this is unclear, go ahead and ask. Likely though, a little research into any of these topics will lead to the answer and a deeper understanding of forced induction, so I’ll likely just point you in the right direction. Google is your friend.

[Rinkrat456]

Let's add this (http://mys10.net/showthread.php?t=6165) thread as if it were part 1 of this thread since it's been sticky'd.

[Injected]

Let's add this (http://mys10.net/showthread.php?t=6165) thread as if it were part 1 of this thread since it's been sticky'd.
That was actually the link that was supposed to be in the fourth paragraph. I posted it and then went out (just got back 4:05AM) and just realized that the link didn't take. I'd actually like to see that thread stickied if we are going to consider it part one. The 'Compressor Calculations' thread isn't technically done, but there isn't much more to explain. Perhaps I'll finish that next.

On a side note: thanks to whoever thought this was sticky-worthy and for making it readily available.

Also, I'm very willing to help people with deciding what parts will fit their application if they are having trouble understanding why something may or may not be good for their purposes, but I don't want to get a million PMs asking, "is this a good turbo?" And if anyone does PM me, I may respond in this thread so others with a similar question can see the answer, or a point can be made.

[97v8s10]

Wow! Exellent post. A lot of good information. I might have to look more into this whenever I get my truck done and start another project.

[Rinkrat456]

On a side note: thanks to whoever thought this was sticky-worthy and for making it readily available.

I believe it was Shug (02whtxblazer) who sticky'd it.

[Rob]

Great write up Injected. I hope people look at this prior to asking a hundred questions that have been already asked, but I highly doubt that.

Also, I'm very willing to help people with deciding what parts will fit their application if they are having trouble understanding why something may or may not be good for their purposes...

He's pretty good at helping people out. I know he has on my project.

[Injected]

I wanted to add to my original post a few points that in my haste to get an answer out, I may have overlooked a point or two that’s worth mentioning to anyone still considering this for a project.

Waste-gates revisited: An internal gate will work fine so long as the pressure across the turbine is less than the pressure in the exhaust pipe. On smaller, and some medium sized turbos, the manufacturer includes a port cast on the turbine housing that has a door and an actuator (together they are the internal waste-gate system). This is typically cheaper and more compact, so is perfect for the automotive industry. The problem comes when the airflow through the turbine reaches the point where the tiny restrictive hole is still more restrictive under the maximum desired boost level than going across the turbine. This can cause uncontrollable spiking, which can over spool the turbo and/or cause detonation.

Another thing to consider with the waste-gate is what to do with the diverted exhaust. You see, a lot of people (and all auto manufacturers) reroute the exhaust that is bypassing the turbo (meaning going through the waste-gate) back into the exhaust system. What sometimes happens is when a very large exhaust is put on a turbo, the pressure across the turbine is sometimes less restrictive even with the waste-gate open, so the turbo continues to spool out of check. This is obviously a problem. The ideal setup would be to reroute it as far down the exhaust system as possible (as far from the compressor as possible) so that the bypassing exhaust finds lower pressure when it finally makes it back into the primary exhaust stream. A simpler way around this, which is neither pleasing to the ears, nor mother nature, is to use what is commonly known as an “external dump,” which is usually a small diameter pipe that comes off the waste-gate (internal or external) and routes the exhaust underneath the engine compartment.

I’m sure I’ll come back and revisit more topics later, but a little at a time and answering questions is enough for now.

[Danny_SS]

everything Injected said plus:
READ, READ, READ. Get your hands on good turbo/supercharger books like "maximum boost" and "supercharged" by Corky Bell
There is also a guy that Injected likes to reference that does a lot of sport compact stuff look for it. Also read Technical articles about forced induction, not just the fantasy advertising ricer stuff you see on most magazines all the time. Remember this project will be the result of you learning and applying that knowledge, not putting together a bunch of random ideas.
Also, If you are planning to tune your own custom forced induction system get tools like a good wideband a/f ratio meter, among many testing tools.

[ptous99]

I wanted to add to my original post a few points that in my haste to get an answer out, I may have overlooked a point or two that’s worth mentioning to anyone still considering this for a project.

Waste-gates revisited: An internal gate will work fine so long as the pressure across the turbine is less than the pressure in the exhaust pipe. On smaller, and some medium sized turbos, the manufacturer includes a port cast on the turbine housing that has a door and an actuator (together they are the internal waste-gate system). This is typically cheaper and more compact, so is perfect for the automotive industry. The problem comes when the airflow through the turbine reaches the point where the tiny restrictive hole is still more restrictive under the maximum desired boost level than going across the turbine. This can cause uncontrollable spiking, which can over spool the turbo and/or cause detonation.

Another thing to consider with the waste-gate is what to do with the diverted exhaust. You see, a lot of people (and all auto manufacturers) reroute the exhaust that is bypassing the turbo (meaning going through the waste-gate) back into the exhaust system. What sometimes happens is when a very large exhaust is put on a turbo, the pressure across the turbine is sometimes less restrictive even with the waste-gate open, so the turbo continues to spool out of check. This is obviously a problem. The ideal setup would be to reroute it as far down the exhaust system as possible (as far from the compressor as possible) so that the bypassing exhaust finds lower pressure when it finally makes it back into the primary exhaust stream. A simpler way around this, which is neither pleasing to the ears, nor mother nature, is to use what is commonly known as an “external dump,” which is usually a small diameter pipe that comes off the waste-gate (internal or external) and routes the exhaust underneath the engine compartment.

I’m sure I’ll come back and revisit more topics later, but a little at a time and answering questions is enough for now.
i've read tech articles on other forums but nothing like what i just read!!! that was excellent, oh buy the way middle school math yeah right.i'll be looking for your next write up. i'm learning alot.

[Rob]

...oh buy the way middle school math yeah right...

Actually it is. Unless you didn't do simple algebra in middle school.

[Injected]

Actually it is. Unless you didn't do simple algebra in middle school.
Well, that depends on a lot of things like what state, school district, school and specific classes you were enrolled in during middle school. The hardest thing I've done in those calculations is roots (7th grade for me) and extensive order of operations (6th grade).

Thanks ptous99 for the words of encouragement.

[boosted_s10]

hey good article
I was wondering if you, or you know of anyone who has done a turbo on a 2.2l
I have a 94 S-10 that I put a turbo on last summer, it runs real strong,
5.0l eater hahaha
as far as I know I am the first one in ottawa and possibly canada to do this to an obd1 94
s-10
thanks

[Rinkrat456]

Boosted_S10 can you go into detail about what you did exactly?

[Rob]

Boosted_S10 can you go into detail about what you did exactly?

Yes, more details are needed.

[boosted_s10]

Hey as for details
engine is .20 over
weisco pistons, eagle h-beam rods, ballanced and blue printed, studded top and bottom, aftermarket head, o-ringed the block.

turbo setup is completly custom, 14G turbo (too Small),, exhaust manifold, downpipe. charge pipeing all custom fab'd. intercooled with a blitz blow off and a turbonetics wastegate.

fuel management by smt. with 550 injectors.

running 11 psi, haven't put it on the dyno yet but we figure around 280 rwhp.

as for the truck itself.
it's a 94 white reg cab short box, 18 x9 boss wheels dropped 2 & 3
this winter's project was to to the 04 s-10 conversion kit with grill and lights and a bumper from street scene.

any other questions feel free to ask

[boosted_s10]

this one is for all the 4.3 guys.
a good friend of mine who actually did the turbo setup on my 2.2, had a olderstyle 4.3 s-10 that he did the turbo setup on, the truck was insanly fast. he sold that and just recenly bought another s-10 this time a 94 with the 4.3, again he did a turbo setup on it. he will be starting another project on a 03 xtreme 4.3, this one will probably be a twin setup.
4.3's can be turbo'd and yes i agree that the 2.2 does have more room under ther hood but try and stuff additional injectors in the 2.2's intake. not as much room as you thought, look for another way of adding fuel.

[Rinkrat456]

Injected, I was wondering if you could take a peak at this whenever you have nothing going on. By no means am I in a rush to get this setup moving along, I'm just learning about supercharger selection by boosting a theoretical 4.8L V8. The goal of this engine is daily drivability and torque increase. The hypothetical Vortec 4.8L V8 is a motor that would go in a hypothetical S10 ZR5, 4WD automatic transmission and suited for a 16-18 year old girl in high school. If you looked at my "Attn Dimemaestro" thread I have going you'll see a more in depth version of the V8 swap. Dime said to turbocharge the motor, I'm supercharging it for learning purposes. Link (http://mys10.net/showthread.php?t=6992)

What I'm trying to do here is match a supercharger and intercooler that will improve low rpm torque and deliver extra power at cruise for better fuel efficiency on the highway. Redline is 6000rpms, highest shift point is 5500rpms. Redline power is about 99/100 on the list of things to worry about since this is a 4WD V8 with oversize tires and is a daily driver. If the selected supercharger improves power output all the way to 5500, woohoo.

Now first I was looking into camshaft selection. This is completely up for change, but as I was following Dimemaster's train of thought in selection I came up with the camshaft below.

I'm looking for something that will provide torque and throttle response for a 298ci engine. Since there isn't a market for 4.8L camshafts I look to it's family of LSx motors. In Dime's words, correlating from different cubic inch motors we have to figure each 8% increase in displacement will bring the rpm down 250rpm. I know there is a large market for LS1 350ci camshafts and doing the math, 298ci/350ci =.85. I’m doing this backwards from his model so correct me if my thinking is wrong, but if I multiply 85% to any LS1 cam it should pull that number in the 4.8L.


COMP cams has a camshaft (P#54-408-11) that has an operating range of 1000-5800rpms. 85% of that equates to a cam that does 850-4930rpms. A bit low, but that's ok since it will provide stump pulling low end torque, great midrange and red line isn't a main objective anyway.

Camshaft specs:
Cam Style: Hydraulic roller tappet
Basic Operating RPM Range: 1,000-5,800 RPM
Intake Duration at 050 inch Lift: 206
Exhaust Duration at 050 inch Lift: 212
Duration at 050 inch Lift: 206 int./212 exh.
Advertised Intake Duration: 259
Advertised Exhaust Duration: 265
Advertised Duration: 259 int./265 exh.
Lobe Separation (degrees): 112

Onto supercharger selection. I just deleted a lengthy write up with all my work showing how I selected an S-trim supercharger, but after talking with Rob I’m wondering what is a better choice to start with? A centrifugal or twin screw? I’ll wait for your answer and then go from there.

[Injected]

Injected, I was wondering if you could take a peak at this whenever you have nothing going on. By no means am I in a rush to get this setup moving along, I'm just learning about supercharger selection by boosting a theoretical 4.8L V8. The goal of this engine is daily drivability and torque increase. The hypothetical Vortec 4.8L V8 is a motor that would go in a hypothetical S10 ZR5, 4WD automatic transmission and suited for a 16-18 year old girl in high school. If you looked at my "Attn Dimemaestro" thread I have going you'll see a more in depth version of the V8 swap. Dime said to turbocharge the motor, I'm supercharging it for learning purposes. Link (http://mys10.net/showthread.php?t=6992)

What I'm trying to do here is match a supercharger and intercooler that will improve low rpm torque and deliver extra power at cruise for better fuel efficiency on the highway. Redline is 6000rpms, highest shift point is 5500rpms. Redline power is about 99/100 on the list of things to worry about since this is a 4WD V8 with oversize tires and is a daily driver. If the selected supercharger improves power output all the way to 5500, woohoo.

Now first I was looking into camshaft selection. This is completely up for change, but as I was following Dimemaster's train of thought in selection I came up with the camshaft below.

I'm looking for something that will provide torque and throttle response for a 298ci engine. Since there isn't a market for 4.8L camshafts I look to it's family of LSx motors. In Dime's words, correlating from different cubic inch motors we have to figure each 8% increase in displacement will bring the rpm down 250rpm. I know there is a large market for LS1 350ci camshafts and doing the math, 298ci/350ci =.85. I’m doing this backwards from his model so correct me if my thinking is wrong, but if I multiply 85% to any LS1 cam it should pull that number in the 4.8L.


COMP cams has a camshaft (P#54-408-11) that has an operating range of 1000-5800rpms. 85% of that equates to a cam that does 850-4930rpms. A bit low, but that's ok since it will provide stump pulling low end torque, great midrange and red line isn't a main objective anyway.

Camshaft specs:
Cam Style: Hydraulic roller tappet
Basic Operating RPM Range: 1,000-5,800 RPM
Intake Duration at 050 inch Lift: 206
Exhaust Duration at 050 inch Lift: 212
Duration at 050 inch Lift: 206 int./212 exh.
Advertised Intake Duration: 259
Advertised Exhaust Duration: 265
Advertised Duration: 259 int./265 exh.
Lobe Separation (degrees): 112

Onto supercharger selection. I just deleted a lengthy write up with all my work showing how I selected an S-trim supercharger, but after talking with Rob I’m wondering what is a better choice to start with? A centrifugal or twin screw? I’ll wait for your answer and then go from there.
The short answer to your questions is that a roots style charger (twin screw) will be better for your intended purposes. A properly matched centrifugal charger will be sluggish until the last third to quarter of it's operating rpms.

Dime's noted that there are differences in the supercharger and turbocharger oriented camshafts. Turbochargers like less overlap due to the back pressure generated from the turbine. It should be noted though that the turbo guys are pushing even that envelope, running 272/272 I/E combos on the street and some even larger duration camshafts (282/282 I/E) with a lot of success.

And on that note, I cannot wait for Honda's VTEC to become an industry standard... Imagine the possibilities: running a conservative lobe until you a given load and rpm, them BAM, full out race lobes kick in. Street manners and no-compromise performance.

[s10ls]

there is some excellent information in this thread, thanks to injected for posting it.

having a turbocharged 4.3 in my 94 has been an absolute blast, my truck is a monster lol. i am much happier with the turbo then the old supercharger setup i had before. i wish you had posted this thread a year or two ago when i was still building/planning my build, it would have saved me some headaches lol

[Danny_SS]

turbo 94 4.3 huh? I want to see pics, describe your setup. Are you using a SYTY setup? How about intake manifold. I would love to build something like that and I am sure others will appreciate the info as well.

[Rob]

turbo 94 4.3 huh? I want to see pics, describe your setup. Are you using a SYTY setup? How about intake manifold. I would love to build something like that and I am sure others will appreciate the info as well.

http://www.s10forum.com/forum/f30/project-slow-resurrection-turbo-200434/

[Rinkrat456]

Even the 2114 conversion. Rob, this guy must be your idol lol.

Nice lookin setup s10ls.

[Rob]

Even the 2114 conversion. Rob, this guy must be your idol lol.

Nice lookin setup s10ls.

I'm surprised you haven't seen his set up before. He's over a S10Forum mostly. It is done very nicely.

[Rinkrat456]

I'm surprised you haven't seen his set up before. He's over a S10Forum mostly. It is done very nicely.
I'm hardly in the forced induction forums. You'll find me in the Liftin' It forum and sometimes the V8 forum.

[s10ls]

yeah i spend most of my online time at s10 forum. rob posted the link to my project thread, but that thread lost all the most recent changes when the forum crashed. i have since replaced the small gt30/17c hybrid turbo with a much bigger PTE turbo, tial 38mm external gate, snowperformance meth injection, billet dizzy and msd ignition box and lots of other stuff, and off course lots of time datalogging and sitting behind my laptop tuning lol. and the 2114 conversion, i couldnt be happier with it

i went to the track a few weeks back and made 2 runs, blew off an intercooler hose before the 1/8 mile each time and let off. still managed to trap 80 mph coasting through the 1/8 though

pics

http://memimage.cardomain.net/member_images/7/web/691000-691999/691777_105_full.jpg

http://memimage.cardomain.net/member_images/7/web/691000-691999/691777_106_full.jpg

http://memimage.cardomain.net/member_images/7/web/691000-691999/691777_111_full.jpg

btw rod how is your supercharger setup coming along?

[Danny_SS]

real nice work.
BTW what Throttle body are you using?

[Rob]

...btw rob how is your supercharger setup coming along?

Almost done. One or two weekends and it'll be out of the garage. The big things left are oil lines, FMU, gauges, hook up the BOV and make a base tune. I'm going to update my S/C thread tonight, so check it out later.

[s10ls]

will do, i noticed i mispelled your name after i posted it but i guess you cant edit your posts on this forum lol

and danny my TB is a holley billet progressive 4 barrel, 1000cfm. it has a standard carb flange, i use it with a 2 inch spacer to clear the fuel rails