how much psi can the stock intercoolers take?

[93formula]

just wondering how much psi the stock intercooler can take? i know that the stock inlets are a but restrictive so im planning on getting bigger ones welded on. im plannign on runnign this with a vortech s trim.

 

[turbo buicks]

quite a bit id say. mines seen 30. im sire others have tested them at higher pressures. what car is this on? remember tho as flow goes up pressure drop increases.

 

[93formula]

thanks for the reply, its going on a 93 firebird formula, lt1. im using a vortech s trim supercharger.

 

[turbo buicks]

should work fine. how much boost you planning on running? if i remember my friend told me the stock intercooler has like a 2 or 3 psi pressure drop but im not sure at what cfm number that was at.

 

[93formula]

i was planning on 6 lbs of boost but if it saps 2 to 3 psi perhaps i should run 9 lbs. i think it should handle that.

 

[turbo buicks]

maybe. i dont know what he said the exact psi drop was but i know it wasnt too good. oh well experiment and let us know the results.

 

[d0n_3d]

i've run 27 psi through my stock intercooler before, no problems...it just becomes a restriction when you run that much boost...the more boost you push through it the less efficient it becomes...

 

[fitz3820]

I would give the stock I/C a leak test, they are pretty old now and have corroded. I have seen some that look good but leak like mad when you put them underwater and some compressed air in them.

Mark F. 87 GN 11.9@ 115

 

[93formula]

hmmm good point, i guess ill be taking a risk with one then. better cross my fingers then. will it be repairable or would i be stuck with a paper weight?

 

[BlownZ]

You can pick em up cheap, any radiator shop can test them and as long as the damage isn't catastrophic it could easily be repaired. As far as PSI it will easily take the output of an S-Trim. I had the S-Trim setup on my 97 Z28 and I loved it.

 

[93formula]

thanks for settling my mind!

 

[93formula]

just wondering if i should leave the air inlets as is or should i weld on bigger ones? as that seems the be the biggest restriction

 

[turbo buicks]

id do all the mods i could while its off.

 

[93formula]

so i should have bigger inlets welded on? its not on the car yet, and wont be till spring, i still need the piping made up.

 

[turbo buicks]

yes and id say remove any roughness inside the inlet/outlets for better flow. seen poeple say they've gained 2 psi from the dutt neck and its proven to flow more.

 

[93formula]

great thanks a lot! i think ill be very happy with this setup!

 

[BlownZ]

At 6-10 psi I doubt you would see much of a gain from the larger inlet. On a turbo car at 15-20 psi sure but I think the stock IC inlet is more than capable of flowing the volume that 6 psi will produce. Do you know the CFM output of an S-Trim at 6 psi?

 

[Donald McMullin]

FYI

The following is a comparison of a GN (231) and your motor at different boost pressures:

Engine 231 in3 350 in3
Boost 20 psig 6 psig
VE 80% 80%
Compressor% 70% 70%

RPM 5,500 6,150

PR 2.56 1.54
Compressor In 648.2 ACFM 649.1 ACFM
Compressor Out 365.4 ACFM 500.4 ACFM
Corrected Suction 45.1 #/min 45.1 #/min

Note the same mass air flow for different boost and rpm.

This is just a comparison, if you have big heads and cam, and are running at higher rpm the #/min will go way up and could be a problem.

As stated by BlownZ you need to check the mass air flow of your super charger.

Deep Enough
Donald McMullin

 

[93formula]

hmm the mass air flow i dont even know ill have to check into that, my car is speed density so i dont have a mass airflow sensor. ill post back when i find out, thanks

 

[Donald McMullin]

What you need is the compressor map for the supper charger and/or the ACFM/rpm/PR curve, not sure what would be available for your supercharger.

An alternative would be to contact the supplier of the supercharger and give him your operating conditions such as engine in3, peak rpm, engine VE (based on heads and cam) and have him provide the calculations as to your peak air flow through the IC.

If his calculations indicate a flow at or less than my calculations for a stock GN IC, you should not have a problem. If you air flow is more than my rough calculations you will see an increase in pressure drop across the IC and the IC will have a problem in removing the heat from the compressed air.

To test for the pressure drop at different quantities of air flow, you could have the IC tested on a flow bench. This however would not test the IC for heat exchange.

Sounds like you have undertaken an interesting, but time consuming project.

Deep Enough
Donald McMullin