BLOWNBLUEZ06

iTrader: (17)

Listen to Frost. Get a good methanol system to cool things down. My IAT's were 175° without meth by the end of the track. Now 110° with meth.

Phil99vette

iTrader: (11)

How much boost are you running? Figuring a 402 with 17# of boost and a single 3" exhaust, the exhaust is goign to be going around 588fps and your backpressure is going to be high. By changing the exhaust to a 4" unit and a T6 housing, your exhaust velocity will drop to 330fps and you will free up a TON of horsepower. You want Velocity before the turbo, efficienty wastegates, and low backpressure after the turbo.

Just my .02
Headers 1 5/8" or 1 3/4
Crossover 2.5" with 4" long tubes on the turbo
Downpipe: 4" aluminum
T6 housing
60mm Wastegate dumped externally, needs to be on the turbo

If your going to stay around 17-20psi
3" aluminum tubes feeding the intercooler

I've ran the numbers and this combo works. PM me if you have any questions.

z28boysteve

iTrader: (9)

that's an even cappier part, I DO HAVE SNOW! lol.

Im running 11 and change on the dyno, my gauge at the track shows 15 psi but I don't believe it to be accurate.
I run a 1 5/8" header with 2 1/2" crossover and about 6" long tubes up to the T4 flange.. The cold side is all 2 1/2" I have an externally dumped 60MM Tial. 3" DP mounted right up to the 4" outlet! no transition!

I had a backpressure gauge installed but it couldnt take the heat Im guessing and never read. I may try just to get everything settled in, a T6 housing for my PTE88 and see where it takes me.. Remember though Ill always be on the slow side due to Im keeping the 6 speed at all costs. (There is a record I want one day )
I would like 3 1/2" cold pipes though....
Thanks for all the help folks1

mwatson185

The exhaust backpressure cracking the wastegate makes a lot of sense. Do you have a stiffer spring you can stick in there to check?

98Z28CobraKiller

iTrader: (17)

All the under sized piping should just me making the car make more boost. I'm not saying that isn't a problem also but it isn't the current problem. Maybe it wont make power, lay over real early in the power band or have detonation issues, but it should make boost.

z28boysteve

iTrader: (9)

Im in Iraq right now, 3 months left of my third 12+ month deployment. So at the moment I can't change springs, but Ill call tial and ask them about it.

Also I see what you're saying about the thing should be making boost with small pipes.. but hell Im so lost, and I know 2 1/2" isn't big enough anyway I was just going to redo it all for the PT3000 anyway.

mwatson185

It will only make more boost at the compressor outlet due to pressure loss through the small cool side pipes. Where are you measuring your boost, compressor outlet or intake manifold? I'd put money on the WG cracking open because of high back pressure.

98Z28CobraKiller

iTrader: (17)

Is your wastegate tied into the 3" DP? If not, there is no reason for the wastegate to pop off prematurely.

z28boysteve

iTrader: (9)

no its open WG.

IWGF

iTrader: (6)

Hey man, listen to these guys like Josh @ KYTP, the know what the **** is up.
As for your 408 being too big for a PT88, that's a crock of ****, one of my friends and local shop owners put his 408 w/ PT88 into the 9s here in albuquerque, and the car is also a street monster. Just work with your kit dude, don't give up on it, you're already this far in.

lt1camaroman93

iTrader: (7)

That 88mm is PLENTY for a stout 408 if you're looking for an 8 second car. I'm rocking truck manifolds with 2 1/2" pipes to an 80mm with 15psi and down in the 8's. It is a t6 flange with a 5" dp though. Once you get the bugs worked out you'll be happy. It takes time, that's for certain. Mustang Dyno claims I make 588rwhp at 15psi, just an fyi.

z28boysteve

iTrader: (9)

I have no doubt in my mind that the PT88 CAN be an adequate turbo, However with the T4 flange and 3" DP It's not going to to the job. Many people hear are seeing me say the 88 is too small and assume Im talking about the T6 model Im guessing which would be an incorrect statement, the T4 model IS too small.

phildo

iTrader: (7)

It's a flow issue. You went big cubes. An 88 is big enough if it is a t6 with a 4" or larger DP. You have too much back pressure with the t4 and a 3" DP. Even if you put a bigger spring in the gate it is only a band-aid to fix the problem of too much back pressure. Just fix it now rather than later. Either way it will have to be addressed when you go for more power. And you know you will cause you have the addiction! We all do here in the FI section!

engineermike

A t4 with a 3" downpipe isn't optimal, but will support WAY more than 129 in the quarter. I bet it would support over 140, even on a 408. For the 18th time, the turbo/downpipe isn't the main problem here. Many have proved this based on experience. It MAY be the 2.5" cold-side piping, but you can measure dP between the compressor outlet and the plenum to see for sure. Also, a way to make SURE the wg is not opening is to simply install a blank/blind upstream of it. You could make one in 10 minutes. Just be prepared for the carnage associated with 30++ psi boost.

Mike

z28boysteve

iTrader: (9)

While the 3" DP is not THE problem it is however not optimal and after all I've spent on this car I am not going to keep something on the turbo which will adversely effect turbine flow. The real problem is most likely in the entire cold side, it's all wrong, and the intercooler SUCKS I get consistently over 180 degree intake temps, and then I start losing ign. timing after that and I only run 16 degrees of timing at the moment just for the break-in tune.. Will be pumping that up to 21 or so after I re-work the PTK kit. and Build the new cold side and put in the PT3000

Andrew91GT

iTrader: (6)

Here's the old turbo kit I had with a pt88: http://juneau.me.vt.edu/~aweil/turbokit/thumbnails.html

348 hydraulic roller ford, 1 5/8" shorty headers, 2.5" crossover, 4" downpipe. T04 PT88.

Went 5.5's @ 128ish in the 1/8th mile and 8.92 @ 159 banging off the limiter the last 150 feet in the 1/4 mile on BFG radials at over 3300#.

z28boysteve

iTrader: (9)

Yes, I no longer doubt the Merit of the T4 PT88 and its capability of being an 8 second turbo.. HOWEVER that is only when it is properly utilized! I would say myself being around 3800lbs, having a 408 (more BP than a smaller motor), having tiny 2.5" Charge pipe, a completely innefective intercooler, an early opening waste gate, 16 degrees ign timing etc, as well as the 3" DP and numberous other things just in effect render it innefective on my setup, I need to keep what I got, fix the crap that's messed up, and it should make some power then. If it doesn't.. then Ill complain.
It's not exactly close to my dream setup, and I probably never get that turbo in the 8s in my heavy *** car with a 6 speed. It WILL however be a very valuable tool in educating myself on making the most with what I have, and what it takes to get a manual boosted car down the track in a hurry, Ill save the 101 for a 6 Bolt Motor and go max effort with that stuff. KEEPING THE 6 SPEED!