Hello to everyone from Baghdad,

1. This is my first post and I would like to state that the members of this forum are seemingly very informed/experienced. So, I figured I'd start here.

2. I'm currently stationed at Baghdad International Airport until August, so I'm using the available time to assess the overhauling of my '78 (non pace car =(...) I figured I've earned it...

3. I've got a fair amount of experience dealing with Chevy drivetrains after multiple detonations of engines and a few trannys in my 91 Camaro from when I was younger. With that being said, I am conceding the fact that I don't know everything and would appreciate it if everyone didn't assume that I did =D...

4. I have a pretty firm idea of what I am looking to do with this project. I have come to realize that I want to go fairly big without having to bite the big block bullet. I've started ordering parts for a pretty aggressive 434 with the intent of running a carb blo-thru system with twin Turbonetics T66's. With a comp ration of 8.2:1 NA, I'm assuming that after the block is O-Ringed and such that I will be able to safely run 25-27 lbs on 92 pump gas. That's based on my research and what my uncle's buddies think. But they make too much money and don't care if it lasts more than 5k miles.

5. The problem lies within #4. In order to boost that much...I couldn't realisticly expect to jam that much hot air into an engine and keep all the forged internals non twisted. So there's the problem, with all the looking I've been doing. I have been unable to find a suitable intercooler set-up for my beloved C3. I was contemplating twin side mount intercoolers near the bottom of the engine bay, but as i'm in Iraq, i have no way to visualize/measure the engine bay. Also I'm encountering a lack of suitable front mounts, not too mention the airflow isn't all that great to begin with for cooling purposes.

So before this gets ridiculously long, please pass on any suggestions or questions that need clarifying, and any and all help is appreciated. You all have already helped so much.

 

First, and foremost, thanks for serving.

Can't help you with the pressure-cooker, but can make some suggestions for beefing up your driveline to handle the extra power you'll apparently be pumping out.

1) Solid Spicer U's, throughout. BTW, the stock 3" 1/2-shafts the '78 got are pretty stout.

2) Solid diff x-member locating kit, including front diff biscuit.

3) If you've got a stick, lightweight flywheel.

4) 1/2" lugs in the rear stubs.

5) If you can swing it before you break the stocker, upgrade to a 12-bolt IRS diff. This could be one of those "pay now or pay later" deals.

6) If you lower, watch your 1/2-shaft angles. There's several reasons, and a few solutions and/or crutches...

Arrive back home safely from your tour.


PS, fill out your profile when you get a chance.

 

I can't help you with the pressure cooker stuff either but do appreciate your service over there. I'm involved with homeland security issues on this side of the pond so keep abreast of the efforts on both sides.

My 78 corvette work and study leans toward originality but it fascinates me with what others do. I've got a 2000 convertible with 345 hp and its funs...much more and I would probably get into trouble.

But do keep us posted on your ideas...others will contribute along the way.

 

Well, it appears to me that my 78 has fantastic airflow to the radiator. I have removed my front grilles and turn signal lights, my front bumper support/ vacuum tank, and my ac condensor. Now I can easily see the front of my radiator when I look through the front bumper. So you might want to consider junking some parts in the name of airflow.

My first thought for a good intercooler location would be right where the ac condensor use to be. You could mount a huge intercooler right there. If you want me to take measurements of the front of the radiator support, just let me know.

The best way to run the piping to and from the intercooler would be to wrap the pipes right underneath the radiator support, bring them up on the other side of the radiator (pending that you have electric fans for clearance) and shoot it right into the intake. Can you visualize this? You would have to cut through the front air dam for the intercooler piping. There would not be any clearance issues doing it this way. My car is very low to the ground (550 coils minus half a coil) and a 25" tall tire. It looks to me like a 3" pipe would fit fine right underneath the radiator support with no clearance problems.

You could also wrap the pipe around the sides of the radiator support but you would have to cut the inner fender and your tire would probably rub on the pipe in a tight turn.

 

With that much boost on 92 pump gas, you'll be lucky if that motor lasts 5 miles. The effective compression ratio will be 22:1. Maybe if it was a diesel.

I ran a 427 with 5.6:1 and 22 lbs of boost with an 8-71 huffer. Effective comp ratio was 14:1. Still needed 110 octane fuel.

Heres a boost calculator.
http://www.rbracing-rsr.com/compression.htm

 

I am running a 355ci with a 144 supercharger,8.6-1 compression and 7-9 lbs of boost, in my chevelle. This is borderline scary, and thats the way I wanted it. My next project is putting in a methanol/water injection, which is basicly a chemical intercooler. You might look into them as an option. Thank you for protecting my freedom, and come home safe!!

 

did u see Nov 07 CarCraft
TT +stock 355 runs 9.74 @ 141.
So i gather u r building a drag only car w/parachute?

 

Thanks for all the input so far, however, still have a question or too now that you've answered.

1. Based on my conversations with ATI and Whipple, 25 lbs on 8.2 should be "relatively" safe so long as I have a sufficently efficient intercooler. I'm a little lost in the math of how the comp ratio will be nearly tripled. ATI was adament when telling me that 20 would be more than safe with a centrifugal supercharger on 92 octane. Further input would be appreciated.

2. I intend on switching out the dilapidated 350 tranny for a nicely beefed up T56 (I understand the inherent driveshaft tunneling work ahead of me) and 3.73 rear gears. I am a little stumped still on the suspension pieces but luckily with my uncle owning a GM dealership I have a wealth of resources in that regard. (unfortunately everyone of them is a die hard NA BBC guy so...here I am)

3. In regard to an intercooler mounting where the AC components were located, it would probably work but I' thinking it might interfere with the intake to the passenger side turbo...I was more looking into if anyone knew of any pre fabbed front clips that would have adequate room for a large front mount intercooler...But they seem to be nonexistent...Ah well, my search will continue until I find something...I might have to just settle and have a custom urethane front end made...But not much grows in the desert over here...Especialy not $$$

Thanks again

 

I have a T56 in my 78 (orig TH350), I can help out there if you need it. The tunnel needs to be hammered a bit around the center of the trans and it needs to be cut for the larger shifter, that's all. No major mods.

 

Are you actually in the service?? Or do you work for KBR? If you are in the service, what division are you with??

 

I have a 72 big block with twin turbos and a blow through setup. I have had it on the road for 3 years now and run 15 lbs boost through it on 91 octane pump gas. I made a little video on how my car is setup and planned on doing an intercooler one day but I seem to get along ok without it at the current boost level. I have an intake air temp guage and unless its 85 degrees plus, my intake temps dont exceed 180 degrees or so. If you are planning on 25 lbs of boost, you will definitely need some sort of cooling. Maybe a water injection setup would be easier to make room for than an intercooler? Do you realize how much power you are talking about at 25 lbs boost?

http://s73.photobucket.com/albums/i2...ngthevette.flv

 

This is copied from BDS's web site:

Final compression ratios in excess of 12.4:1 are not recommended for use with "pump gas." The higher the final compression ratio, the higher the octane rating of the fuel must be in order to help prevent detonation and serious engine damage.
The formula for calculating your exact final compression ratio is as follows:
Final Compression Ratio (FCR) = [ (Boost÷14.7) + 1 ] x CR

Boost = Maximum blower boost
14.7 = psi at sea level
CR = engine compression ratio

http://www.blowerdriveservice.com/techcharts.php#final