About the Stealth Ram (judging from the pictures) - The Plenum looks a little on the small side. This will mean that maintaining boost levels under increasing throttle will be difficult. The runners are longer than "ye olde" intake, but longer is better for these applications. Hence why you see engines that the plenum feeding the left bank is over the right head with long runners coming across the engine. The longer the better (to a point of course). It would also be a little better if the manifold wasn't split into two throughput sections (two 4bbl type areas). It works a lot better if it was just one open channel to feed all eight runners. That valley between the two tunnel areas would have been better used as more air storage. Overall, it's not a bad design - but it could be better. There are obvious overtones of their heritage as an "old school" designer in the way it's done. For combining max turbo efficiency, with adding FI to the engine, and keeping cost in mind - you probably won't find a better pre-made unit. If you made one by hand (from sheet metal or such), you could get more performance.

As for your desired boost levels - Low boost is generally assumed below 10psi, 12psi max. For a engine that is designed for Normal Aspiration these drop to below 5psi, 8psi max. Yes, the assumed threshholds of what is "low boost" are set rather low. This comes from the fact that most import engines are very high flowing engines to begin with and if you boost much on them you blow heads.

Thanks for the prompt response. My basic game plan for my engine is, I cannot forsee my future financial situation but Right now I have a pretty good normally aspirated small block chevy. I got Aluminum Trickflow heads with 180cc intake runners and they flow very well. My compression ratio is 10.3 and I have forged pistons with a comp cams 270h magnum cam in it that has 224 duration @.050 and .470 lift for both intake and exhaust at 110 lobe sep. I am using 1.6 roller rockers. My power is about 390 hp and 410 ftlbs. I plan on saving my top end for the turbo engine but redoing my short block for lower compression, forged crank, forged connecting rods, and a good cam for turbos. This wont be for another 3 years since I am returning to school in january and will still have 2 years to go for my degree. But like I said I am thinking of buying a EFI kit for the summer enjoyment and improve the overall drivability of the vette.

You think a tuned port manifold would be better for a turbo app? since its got long skinny runners?

You appear to have a very similar set up to mine. I bought my Vette with the engine already set up as a 383 Stroker, so I don't know specifics - but that's pretty close to what the PO claims. You also have a similar plan - use the V8 for the low end, and the turbos for the high end. The problem you run into with this is getting a turbo "mapped" correctly to the flow you are expecting in the engine. This is heading into higher level turbo theory and engineering, so I'd rather not get farther than that right now.

It is a solid plan to use. You do appear to have a engine that is heading towards being prepped for this style of turbo use.

One thing I had forgotten to mention in that long post - you can intercool Turbo's and Centrifugal Blowers but not regular superchargers. Intercooling can add about 10% more efficiency at the expensive of responsiveness and the amount of work being put on the turbo. Theorhetically, a maxed out racing turbo system (ie F1 style, CART, IMSA, etc) will be running in excess of 80% efficiency. Losing 20% of the work put into compressing the intake charge may sound like a lot, but some loss has to be taken since we can't change the laws of physics and not heat air as we squish it

If you want to get deeper into matching turbos and what to look for - start a new thread on it and I'll keep going in there

I do have a grasp of the concepts needed to be done to turbo my engine. I have read the book "maximum boost" by Corky Bell, from that book is what most of my understanding of turbochargers come from in a hotrodders perspective. My degree is in marine engineering, so from that perspective I am learning how to fix and maintain huge ship's diesel turbos. But this is only book knowlege, I have never had the experiance of designing and building an actual turbocharged car. So I hope you will still be in touch in the future for I will have a lot of questions.

Maximum Boost is an AWESOME book. It is still regarded as the most cmprehensive guide in turbocharging. I own one also, and reference it greatly. In there you can get through all the turbo mapping and other stuff that I would have gone through - so thanks for saving me from writing all a second time

I will be around for many years now. I'm figuring I'll die before the Vette does and so long as I have the Vette, I'll be here

lemme just interject for a quick moment. if I was going to go EFI, and I said...hey, let's call up Banks Power and order one of their 350 twin turbo crate engines, and drop it in the vette...

http://www.bankspower.com/twin-turbo-products.cfm

What kind of horsepower would I need for high 10s, low 11s. Just so I have an idea the kind of power I should ask for when I call em tomorrow. (also taking into consideration traction loss and driver reaction time)

|UPDATED|11/7/2004 8:32:03 PM (AZT)|/UPDATED|

okay my last post was as I was heading out the door to go to work. the idea that has jumped into my mind is this. buying a 350 twin turbo crate engine from Banks power and having ONLY the plenum chamber and the boost tubes polished and plated, nothing else. I can remove the valve covers and put on some polished Edelbrock covers, maybe a chrome dress-up kit and an air cleaner. (when I had my original price check from Banks, I think they had the entire engine and turbo system polished and plated, and I told them I'd like to be able to switch between premium gas and 100-octane fuel, so I don't know is there was another ECU for the 100-octane, or if they did something with the injectors, so that I could do this, because on the site...I quote..."The fuel injection and engine management system was recalibrated for the octane of the gasoline being used." I figure that between having the entire engine polished and plated and having the 100-octane fuel option, whatever it was, the price of the product was raised.) So...my theory is...get the bare minimum horsepower I need for the time I want...have only the tubes and the chamber polished and plated, then use cheap dress up kits...that way the visible part of the engine looks pretty, who cares about the rest...and forget 100 octane, I'll just run premium gas all the time. Scratched down to that, I'm wondering how much it will cost, and as soon as I wake up, I will call and ask about price, payment options, etc. I'm thinking...maximum boost, 15 psi. I like concept of electronic boost control, push a button on the dash to switch between 5 or 6 psi for street driving and 15 psi for racing. if I can switch between psi, the engine'll be more streetable. I'll look into that later. anyhow, horsepower I'd need to run low 11s, high 10s?

With proper gearing, good traction tires and a good driver reaction time assumed. To move 3600lbs of car and driver down the strip in a comfortable ten seconds, about 650-700 hp is needed. Since it is an automatic maybe 750 hp but you can't misshift an automatic once its set up right. So my guess with the good flowing heads and a proper turbo set up 13-15 lbs of boost is the required amount at the strip. 6-8 lbs is good for street fun for around 450-500 hp. Love the turbos versitality. I still think the cost will be sky high at Banks engineering for the turn key motor. You can save a ton, I think if you handled the actual motor and EFI your self. You can still buy the turbos, exahust manifolds, wastegates, and oil feed plumbing from them. I think they quoted me around $5000-$6000 for those. Looks like we got enough experienced guys here that can help you pick out the rest if you like. But Banks will put a warrenty on there motor and its all done for you already. You just drop it in your car and your done.(at least motor wise) Its your money and your call.

Wow, Looks like I have missed out a bunch during my absence. Sorry I have not been able to join in on the topic here, but I have been at SEMA for the past week.

So Far here is what I see being debated and I would like to offer up some suggestions.

Carbs?
EFI?
Supercharger?
Supercharger EFI?
Turbo?
Turbo EFI?

Let me first say anyone of these combinations can be used on the street and all are currently being used with great success. It all boils down to time and money and working with the right parts and people.

10 Second Quarters only makes your goal more challenging. If you want to run 10's in a C3 you will need 700 RWHP. No if ands or buts about that. In my 8 years working on various projects with many magazines and todays parts 700HP on 91+ octane can now be easier to acheive then ever.\

To name a Couple:
Billet Specialities, Chicayne Built By Troy Trepenier, 1200 HP Twin Turbo EFI. Street Driven

Malitude, Built by Mark Stielow, 1100 HP Twin Turbo

Aftermarket EFI systems like FAST, Accell DFI, Holley Commander 950, Motec, AEM, etc are all fantastic units. Some have so many features you will never use them all and it really makes their units expensive. What you need to remember is the ECU is a brain or if you like think of it as an orchestra condoctor, directing information to the outputs and inputs to the engine so everything runs in harmony. It could care less what type of engine it has been attached too.

All of these units will work with a supercharger or turbo system, you just have to set up the initial parameters in the software so it knows it will know the engine is force inductioned. You also need to have the right Map sensor for a boosted type system.

Combining EFI with A Turbo or supercharger can be very costly. So what are some alternatives that I believe you should consider.

First if you are looking for a viable supercharged engine that makes 700 HP then check out the cover of this months (DEC 04) SuperChevy Magazine. This is an engine that I helped put together with Vrbancic Brothers Racing in Ontario California. We chose all off the shelf parts. No custom built parts which make it a very viable option.

You could also do the above engine with EFI on a block through MPI setup or a TPI style intake.

Lastly, and this would be the route I would go would be nitrous Oxide. This will let you build a very streetable 500HP big inch small block, something like a 427 CID. Then when you decided to take it to the strip you could spray 200HP shot into the engine when needed to run 10's.

I think you will find the nitrous much easier to install and maintain then trying to cram a twin turbo, or supercharger system into the engine bay of a C3. That alone would be expensive and costly.

One last thing. Your talking alot about your engine. Don't forget about the rest of your car. If I've seen it once I've seen it a 100 times, with big power comes big breakage. If you ever wanted to find the weak parts in any system, then 700 RWHP will do that for you real quick so be prepeared to spend lots of money now or later to get those systems in order. Those would be Transmission, Drive Axles, Differential, Bearings, U-Joints, ETC. And don't get upset if you start to see stress cracks in the body created by that much power.

You will also need to address the fuel system.

Let me say if you have never driven a car with 700 RWHP then you might be in for a shock. You can make them streetable, but you have to drive them with a very soft foot as it does not take much to send yourself propelling out of control. Been ther done that and to be honest you will get tired of it really quick.

Thats my opinion and some additional food for thought.