69-chvl

iTrader: (11)

Can I insert a "t" in my boost ref. line to the w/g's to get an idea of pre i/c pressure? Everything on the cold side is alum and I don't have the capability to weld it. This would be a MUCH easier solution just to get a couple of readings.

JoeNova

Yes you can.

Hank Peabody

iTrader: (2)

Are you going to log it on the Holley efi? I keep meaning to look into how to do that with back pressure and pre ic.

69-chvl

iTrader: (11)

Yeah I was going to install a T in the reference line and then extend a hose right over to my oil or fuel pressure sender and just temporarily hook it up. Was going to that to measure PB also.

Hank Peabody

iTrader: (2)

Damn good idea, didn't even think of that!

stevieturbo

Only if your port for the w/g's is before the compressor, and you are not using any form of boost control that bleeds off air on that line.

And ensure anything you're using to take readings is calibrated the same as whatever you are using post IC otherwise they will be meaningless.

69-chvl

iTrader: (11)

Stevie,

My compressor cover is tapped and a line from there goes to the w/g's. I was going to T into here for pre-i/c #'s and then just use map sensor to see what the intake sees. But I see your point, I should probably use the same sensor after the i/c to get a true difference.

I just want to see how if the cheapy i/c is killing power that all. I would imagine my low boost is creating an issue with the i/c but you never know.

stevieturbo

I didnt say you had to use the same sensor. I just said you need to ensure whatever devices you are using to monitor pressure, that they are calibrated the same.

I have a few pressure sensors on my car, and each one when you use the stated calibration for them, all read slightly different than each other.
When I was calibrating them all manually for logging on my ecu, I used a cheapo mechanical gauge...which in itself raised more issues !

I had a gauge on the line, as well as the one on the pressure regulator I was using to apply pressure to the sensors to test/calibrate..

I ended up with about 5 mechanical gauges on the same line during the testing, and there was as much as 10psi difference in some of them !!
Now fair enough some were 0-30, 0-60 and 0-120psi...but the difference was ridiculous, even if they were very cheap.

I ended up using an in-car gauge which seemed the best all round to use as a base and calibrated all other sensor scaling around that.
So whether readings are technically accurate, I know they are all accurate in a relative sense which is ultimately what matters.

And as said, as long as your boost control is w/g only with no other control devices, then yes you could use the compressor port for your test.

oscs

iTrader: (19)

Post up your findings along with intercooler size/brand when your done with the test.

Forcefed86

iTrader: (4)

In for results. I heard as much as a 7 psi drop on the cheapo 32x12x4 china cores at 20+psi.

69-chvl

iTrader: (11)

Just need to rig up a T and I'll report back. Its just a used ~31x12X3" no-name i/c. My IAT
s are so low for some reason (turbo too big) that I wonder if I even need the i/c, or the sucker works REAL good lol!!!

69-chvl

iTrader: (11)

Some interesting data...

I only did a 5100 rpm pull at 11psi, I d!cked with the boost controller hooking this up and was worried about an overboost situation so I took it easy.

Surprising results for low-boost anyway.

Note: fuel pressure = pre-intercooler pressure

69-chvl

iTrader: (11)

Apprx .5psi drop at this level. Closer to .7 down low.

One thing I did notice, that pre-i/c pressure jumps a bit at first then levels out. Guess air is backing-up at first and then is forced through???

Forcefed86

iTrader: (4)

Give 20lbs a go...

GMCtrk

iTrader: (23)

Barely any pressure drop, nice. Are you still running the 75/83, but now on a 5.3?

What kind of IATs are you seeing?

The 75/83 finally pushed my 4900lb truck to 10.9, but IATs are 219F at the finish line.

69-chvl

iTrader: (11)

I would have to change the springs out in the gates which is not big deal, but am more worried about pushing 16psi+ on pump fuel. I cant get this sucker to ingest any meth - she dont like it.

Yes this is the s475, 83 on a T4 and yes on a 5.3. I really can't get the IAT's to climb past 120-130 on a quarter mile pass, with no meth! Makes me wonder if I'm just not pushing the turbo hard enough to make heat, or the i/c is doing its job. For what I do a smaller turbo probably would of been more appropriate.


I'm wondering if removing the i/c would be of benefit, but seeing such a low drop I dont think its hurting anything.


GMCtrk - how much boost are we talking about for that 10.9 run? Race fuel, meth, timing, i/c??? Thanks

GMCtrk

iTrader: (23)

Yeah, you're probably right in the sweet spot for the turbo, so it's not superheating the charge.

Run was 16-17 psi, 11 deg timing due to IAT pull, E85. 20x11.5x3" ebay/china IC. New custom Garrett IC is on order.

Hank Peabody

iTrader: (2)

I tried that last year! I have the same intercooler but 4" thick. I never get over 130* intake temps up to around 15psi. I took it off last year and on the dyno around 9psi I was at 220* intake temps, don't take it off!!!

69-chvl

iTrader: (11)

Great info right there!