Maximum boost?

[2.8/3400 1985 Camaro]

What's the most boost a 60/6 has been known to take? If it makes any difference, I'm specifically curious as to how much a gen 1 block can take, and how much aluminum 3400 heads and manifolds can take, I don't care about any of the other stuff as everything else can be beefed up, just need to know for the things that can't be made to be stronger. Also curious how much the aluminum block can take if anyone knows...

[IsaacHayes]

The aluminum bowtie block? Who knows those are usually too expensive for us.

A gen3 block with roller cam would be a better place to start with. It has cross bolted mains and a structural oil pan. But Mars runs up to like 15psi on a stock 3400, with stock head gaskets. You can always go with MLS, o-ring the heads, whatever. I don't think anyone has found the limit of the heads yet... For high boost start with forged pistons, then forged SBC machined rods, then if you blow head gaskets, address that, and after that who knows what's the next weak link....

Being RWD you have access to strong transmission/drive line parts... So that part at least should be fine.

[2.8/3400 1985 Camaro]

Well I already know how to build for it with other components...and a 3x00 is out of the question as the application is RWD. But perhaps this will get me a better answer, think the heads, manifolds and gen 1 block can take 32 psi of boost?

[robertisaar]

and a 3x00 is out of the question as the application is RWD.

think the heads, manifolds and gen 1 block can take 32 psi of boost?

why would you ever need to stuff over 2 EXTRA atmospheres of air pressure into an engine?

and there are RWD 3x00s out there...

john has a hybrid, and dave and brad are using full FWD blocks IIRC for their ponycars...

[2.8/3400 1985 Camaro]

Yes, I'm aware its been done, that doesn't mean I have the desire or resources to do it myself...as for why 2 extra atmospheres, to wring every bit of hp possible out of a relatively small engine. Chances are I wouldn't run it that high most of the time, but I would like to be able to run with something like say a corvette if the occasion arised.

[IsaacHayes]

LMAO... You don't need 32lbs of boost to hang with a vette.....

Look at Loner666'... he had a FWD corsica, with a 3400 with 3500 top end, cam, and turbo running something like 9 or 12psi and was in the low 12's in the 1/4 with a slipping trans and probably no traction (fwd).

You will have less displacement, yes, but with 3400 heads and boost you will be golden. Port the heads correctly and you'll see even more gains, same for a cam. Go with 3" downpipe (merged). Or larger. Anything after the turbo is a restriction. (the same is not true for N/A, as yo don't want too big of pipe or you loose velocity and momentum of the gases).

And 32lbs means race fuel..... Or such a low compression ratio that it will be a turd until you spool up which means probably very high RPMs before it starts moving...


If you went with a camaro 3.4 block, 3400 pistons and heads (or even forged pistons) with boost and a stock bottom end and 2004 GM graphite head gaskets you'd be in the 12's with a basically stock motor and running under 2 bar of boost (9-12psi). Add a cam and that will only help.

What trans you running?

[2.8/3400 1985 Camaro]

Well my power goal is 500-700 hp, and and for 600 hp that means 32 boost according to boost calculator. But like I said, most of the time I would probably run it at it 8-16 or something.

[robertisaar]

want to hear something that will BLOW your mind?

you can make more power on 5PSI with great heads/intakes/exhaust than a set of shitty heads(take 3800s for example) with 20PSI. all other factors remaining the same(compression/quench/etc), if heads can't flow for shit, they are a restriction.

restriction causes pressure if there is flow.

pressure causes friction, which causes heat, which drops power...

what you should be looking at is how much air(in CFM assuming a constant density) is needed to create your power goal.

[2.8/3400 1985 Camaro]

At 8000 RPMs(redline) and a displacement of 173 CI it will need 440 CFM if memory serves. Not really sure why you mention the heads either...3400s on a 2.8, 3.1 if i stroke it is plenty, especially since once I reach the turbocharging phase they will be fully race ported, along with the manifolds and a 65 or 68mm throttlebody to boot. My knowledge on boost is somewhat limited, but I know what can bottleneck an engine and the impact it can have...

[robertisaar]

http://www.squirrelpf.com/turbocalc/index.php?version=4&target_peak_power=600&pr_ref=14.696&engine_disp=2.8&engine_disp_factor=0&target_af=12&bfsc=0.5&max_ic_loss=2&rpm_redline=8000&rpm_peak_power=6000&rpm_max_boost=4000&rpm_min_boost=3000&vol_1=80&vol_2=86&vol_3=78&vol_4=70&vol_1=80&vol_2=86&vol_3=78&vol_4=70&intake_temp_1=90&intake_temp_2=120&intake_temp_3=135&intake_temp_4=150&turbo_n=1

i'm seeing ~44PSI and 1050CFM on a 2.8 with 3400 heads... though my VE numbers may be off due to using slightly modified 3400 VE.

if nothing shows up, click refresh maps

[2.8/3400 1985 Camaro]

Which is exactly what I came up with.

[IsaacHayes]

358hp has been dynoed to the wheels using a manual and 9psi on a ported but other wise stock 3400...

[2.8/3400 1985 Camaro]

Key word is 3400, note the .6 liters more of displacement I could break 600 with 24 psi on that displacement.

[pocket-rocket]

i'm seeing ~44PSI and 1050CFM on a 2.8 with 3400 heads...

That's enough boost/airflow to make baby Jesus cry! And they make turbos that will support that and spool fairly well, huh? Craziness... Just make me a promise if you build it. You will take it to the next meet and I get a ride, lol.

[2.8/3400 1985 Camaro]

I would need the calculator to verify that the CFM on that is correct, I came up with 440, but the calculator was based off engine RPM and displacement, and one other thing I think, can't recall what..