15lbs of boost just dont feel right?

[mcpherson88]

hello again stinger. so i have completed my build on my 93 foxbody with a 88 tc drivetrain with the help of your site and wiring instructions, and have been daily driving it for the past few months now. Mods are as listed, 255lph high pressure intank pump, gutted upper and knifedged lower intakes, hollowed cat leading to the y pipe that came factory on the TC thunderbird and nothing behind it, good breathing filter, manual boost controller set at 15-16lbs of boost. factory IHI turbo, factory intercooler (although my hoods vent holes dont lead directly to the intercooler, probably some heat soak there). factory injectors, la3 ecu and VAM. 3.73 gears in an 8.8 rear. short story long, it just doesnt feel like it pulls as it should with that much boost. ive owned numerous 5.0 mustangs, a turbo 4 79 pace car mustang with 5 spd swap, and a couple turbo eclipses, and to me 15-16lbs of boost just does not feel like what i expected i guess. is it that fact its a sohc that it doesnt respond to boost like the imports, or lack of motor for the v8 mustangs. or am i missing something tuning wise? i unfortunately dont have a wideband or afr gauge, so i cant say its fuel or air related, or maybe i need to back timing out? (running factory timing, with a little less gap then factory on plugs). even my friends car with a 2.3t swapped in at 8lbs of boost on the 86tc turbocharger, with similar mods and all the 88tc accessories, adjustable FPR and front mount intercooler feels faster to me. maybe i have high expectations, but then again maybe im missing something. timing, AFR getting thrown off on ecu by hollowed cat and intake, high air charge temps from too much boost and no FMIC? im at a loss, vacuum is 19-20 at idle, so i dont see an issue there, fuel pressure was normal last time i tested, octane switch always in regular mode and running 93 octane, runs great except for a slight ping at full throttle after driving for while in warm temps over 85F during warmer months.

[Stinger]

The lack of airflow through the IC certainly is hurting things significantly, and it's causing you to have to run in regular mode with premium fuel (which hurts power as well). Is that the whole problem? It's hard to say without ANY sort of real data to back up your "feel".

I'd certainly verify ignition timing is set to 10 deg BTDC when you pull the spout.

FMIC and 3" exhaust will add north of 60hp at the wheels.

[mcpherson88]

i was under the assumption i should run in regular mode at all times to keep from being too advanced under higher boost or am i not at high enough boost to require any timing retard? or is that hurting power in top/bottom end? also good lord thats quite a difference in power from exhaust and intercooler, sounds like a good bang for the buck. front mount is in the future. as for the exhaust, i planned on running a holset down the road off a cummins, do most of these already have 3" or larger downpipe? or am i going to need an aftermarket one to fit on it. just dont want to get 3" for the IHI setup if the flange is different on the holsets and end up wasting money.

[Stinger]

If you're getting detonation already (from the heat soaked intercooler or improper base timing) then running in regular mode is correct for your particular setup at the moment. With that said, 15psi is the stock level for an 87-88 TC so there is nothing that makes you need to run in regular mode, if proper airflow is getting to the IC, AFR is safe, and timing is correct (assuming you don't hear detonation).

A Holset is not a fun turbo on a stock head/cam. It doesn't reach full boost until about 4000rpm and then the cam is done by 5000rpm. But yes, they use different flanges/designs. Nobody makes a Holset downpipe so you end up having to modify an IHI/T3 3" downpipe for it anyway.

[mcpherson88]

good to know, i guess a front mount is first thing to knock down on the list. would going with a larger turbo like the ones on the older TCs help with air charge temps if i bump boost up to say 17-18 when i get the front mount since i assume the larger one would be more efficient at those boost levels?

[Stinger]

It will help a little, yes. They also support about 30-40hp more than the IHI.