I need some help/advice from some turbo ppl

[Spd Demon]

I am looking to go turbo on my car. Right now the car is carbed and will stay that way.
I have AFR 185 heads, a good size cam,forged pistons,quickfuel carb. And some other stuff. My compression ratio is at 9.5:1. Will that be ok for a turbo set up? I know I have to do a blow thru carb and such, but I dont know what size turbo that I need, I want a little more out of the car though. Thanks for the help

[NC STANG GUY]

How many cubes?

[Spd Demon]

Its a 302 for now,just freshened it up in sept of last year

[boostedcoupe]

What are the cam specs? My car is a blow through set up and I love it. Do you have a stock block? If so a master power t-70 is more than enough and they are resonable price. I went 6.29 on my old master power.

[NC STANG GUY]

Yep,like boostedcoupe said. A 70mm is plenty of turbo.

9.5:1 will be fine. You can usually get away with more compression on a blowthrough setup anyways. The pressure drop through the carb when the fuel is atomized actually pulls quite a bit of heat out of the air charge. Like a mini intercooler.

[boosted91lx]

Yep,like boostedcoupe said. A 70mm is plenty of turbo.

9.5:1 will be fine. You can usually get away with more compression on a blowthrough setup anyways. The pressure drop through the carb when the fuel is atomized actually pulls quite a bit of heat out of the air charge. Like a mini intercooler.

Billy is right. I just finished installing all my old turbo parts on a friends bone stock coupe. Only changes where the head gaskets (Cometic or any MLS is a must IMO) and a Trickflow Stage 2 cam. The factory head gaskets lasted about 2 minutes on the first test drive.

[Spd Demon]

Cam is a Lunati
Here are the specs:

221/232 duration @ 50
526 523 lift
1.6 roller rocker. They are ss if I remember correctly

The heads are AFR 185s with 58cc chambers
It is a 302 stock block with the ford forged pistons
I have an Edelbrock Performer RPM intake on top.I think I have some pretty decent head gaskets but I will have to go through and check my summit receipts.
As far as blowthru,is this something you guys tackled or should I source out one from a reputable company?
I already have a sumped tank,I guess I will just have to run a return.I am running one of the summit fuel pumps,equalivent to a blue holley I think,is that something I should upgrade as well?
Sorry for the questions,I'm new to this and I want to make sure that I know what I am getting into

Btw, hey boostedcoupe, I am right down the road from you in Greer,right off 101 on the Blue Rdige side.

[boostedcoupe]

What is the lobe separation on that cam. The carb is a csu and it has been awesome, I would highly recommend them. The car is in blue ridge at my dads, come by some time and check it out. We are here tonight give me call 607-5957

[boo00st]

the above statement is false about static compression and its responses to a blow thru carb. fuel distribution is not as effective in a blow thru carb application vs fuel injection.. now dont get me wrong blow thru carbs are awesome just dont overstep your limits and believe that because you have a carb that atomizes fuel and lowers iat that 9.5 to 1 compression will take a bunch of boost. in my experiences 9.5 in blow thru equals 15 psi tops, before you start to see some problems. push your luck and pick up the pieces.

[boostedcoupe]

I do not agree with that. Iat are cooler with a carbed set up vs. A fuel injected set up. As long as the rods, pistons, crank and the block are strong enough and you are running the right fuel you could run a lot more boost. I run a lot more timing in my car at 20lbs than my buddys injected car on 15lbs. Both cars are very similar builds and have the same compression.

[NC STANG GUY]

the above statement is false about static compression and its responses to a blow thru carb. fuel distribution is not as effective in a blow thru carb application vs fuel injection.. now dont get me wrong blow thru carbs are awesome just dont overstep your limits and believe that because you have a carb that atomizes fuel and lowers iat that 9.5 to 1 compression will take a bunch of boost. in my experiences 9.5 in blow thru equals 15 psi tops, before you start to see some problems. push your luck and pick up the pieces.

Really? Anytime you can drop the air intake temps....which DOES happen in the carb blowthrough setups much better than the EFI setups...
You can in turn get away with more compression and/or timing and/or boost.
Nobody said it'd allow it to take a crazy amount more. But it will take more than a comparable EFI setup.


fuel distribution is not as effective in a blow thru carb application vs fuel injection..

From an article in Race Pages a while back...by Jason Reiss(excerpts)

There are many misconceptions throughout the performance world, but the performance of a carburetor-equipped hot-rod should not be one of them. Over the last several years, we have seen debates online on various different forums as to which type of combination will make more power, a carburetor or a fuel-injection setup. We have heard of people running them back-to-back on the dyno, and the carburetor almost always comes out on top, no matter how good the fuel-injection tuning is. There are many reasons for that, chief among them that the carburetor will always do a better job of atomizing the fuel than a fuel injector will. Why, you ask? Good question – and the answer is that the carburetor relies on the vacuum signal from the engine to suck the fuel from the carb, which helps it to do an outstanding job of atomizing the fuel and placing it into suspension with the incoming air to the engine. Fuel injection, on the other hand, relies on the injectors to place the fuel into the intake runner directly next to the cylinder head port, which doesn’t allow the air enough time to disperse the fuel and help it to become a mist, which is what helps the carburetor-equipped combination to burn the fuel more completely and make more power as a result.

and

Another interesting point that Rawls raised during our conversation about the engine build was the tidbit that Davis wasn’t even going to be using an intercooler in this car. Inlet temperatures on a blow-through application are much lower than your typical fuel-injected cars, and the reason becomes quite simple when you step back and look at the issue from the outside. “The average inlet temps are between 140 and 150 degrees, but the fuel in the manifold absorbs the latent heat, whereas an EFI manifold only has the air coming in – there’s nothing to pull the heat away until you get to the cylinder head where the injectors are placed. There is also less friction in the manifold from the air flowing over it in this application.” According to Rawls, the injector doesn’t do anywhere near the job that a carburetor does. He stated that the smaller the fuel droplet is, the better it can help to absorb that heat from the turbochargers, and we’re inclined to agree. Using science to make a car go faster – wouldn’t you have paid more attention in high school if you had known?

[boo00st]

im all for a blow thru carb, i was running one and had great luck with it. i have also seen too many blow thru carbs with high compression not like a bunch of timing when it came to high compression. but hey it is what it is.
i completely understand the atomization factor of a carb, but when you look at a single plane intake for a sbf, please tell me it you dont think that distrubution of fuel is equal.

strap a plate under that carb and hit it then shut down and read the plugs. you will see

[Turbo Bob]

I used a self modded Holley 600 on my stock longblock 302.
My only complaint was with cold starts, I would have to crank for about 3-6 seconds. That drove me crazy. May had been a tuning issue on my end, who knows.

http://www.youtube.com/watch?v=hO0cMeZVHY0