Wondering what kind of difference there is when converting to a small t4 based 88mm?

Jose told me a .96 a/r is the smallest I can go which should work fine on my setup. I can currently build 10+ psi on the trans brake, my stall is 3000 rpms N/A and goes to around 3800 at 10psi. I know on a stick shift car the difference in spool is around 800-1000 rpms according to Jose, but what's the difference with an auto?

Car can make 17psi as it sits now and it has seen 20psi in 3rd, but I don't think there was any gain in power. I'm running the car this coming Wed to see how it does now that the temps have cooled off. I was seeing 166 IATs without meth when I last ran the car in august to 11.0 on 16psi.

I'm not afraid to run a little giggle gas either but would like the car to drive nice without it. With this cooler weather we are having (80s) the car is starting to come loose in 3rd gear on the highway (nitto drags) from a 80mph roll due to boost coming in quick.

 

well i dont know in an auto, but in a manual i had a small frame turbonetic T76 .96 ar, with the cutout open id hit full boost, 10psi about 2700 rpm.
with my precision PtE88, im at about 12psi at 4000rpm, not sure when i set it on higher boost as im to busy holding on and trying to keep it straight.

 

Please dont take offense but from reading your sig and what you have into the car I would seriously re-think your combination. If I understand correctly, you're only making 425rwhp on a 76 turbo currently? I see a few things wrong that may help your current combo - your stall is too low, as well as, your gears. I think if you moved up with those first you may see a much needed improvement.

Key here is use what you have first and fine tune it. Don't just keep popping open your wallet and buying bigger and better. People get greedy with anxiety and just want to buy, buy and buy. Try changing your existing combo first before laying down another $1700+ on an 88mm turbo.

Please call if you need help, I hate to see people waste money.

 

Isn't PSI a subjective/deceptive term because of how many variables needed to be considered? If he wasn't running a proper flowing exhaust/intake for this turbo... wouldn't the PSI just be a higher number with a more flowing intake/exhaust at a lower PSI?

 

Damn you are only making 425rwhp on 16psi? A budd y of mine(turbogibbs on here) put down 535 with a forged 364 with a 76mm on 7 cylinders. You got problems somewhere.

 

Boost is defined as positive manifold pressure...or the pressure above atmospheric. There are variables but essentially 16psi is 16psi.

 

You guys jumping onto his dyno numbers....

He is dyno'ing through a th400, stall and 9" rear end... And thin-*** air. I recently had a hand in tuning and dynoing back to back a powerdyne stock LS1 M6 10-bolt and a LS2 stroker A4. The powerdyne M6 put down 434RW and the LS2 stroker (AFR225s, 402", etc) with a built 4l60, stall and 12bolt only put down 419RW. These power levels have netted the M6 powerdyne 434RW car a best to date of 12.0s@117. The LS2 stroker went 11.0s@122.5xx on its first pass with a converter that is giving up some MPH up top...

Just use the dyno to tune.

 

From what ive gathered with zombie's build, hes got a decent setup going and budget has always been in mind. I dont see him throwing big money away. He has an older post also explaining the low #s from the dyno. Dont forget, hes in vegas.

 

No Offence taken, but let me elaborate on my situation for you.

LOL, dynos are very hard to race, heavy and hard to transport to the drag strip. My car made 425 rwhp uncorrected on a mustang dyno. If you look at my track times you might notice that they don't jive with the dyno numbers for a 3800lb car. The car is making around 600 rwhp if you go off my 126mph trap speed. Yes 11.0 is still slow for 16psi on a t76, but it's las vegas and that time was run in august when the track was around 100 degrees at 11pm and the DA was 5000+. IATs at the end of the run were 166 because my meth kit wasn't working due to the temps (need to reloctate the pump and tank).

Everything with forced induction is slow here when it's hot so I know it's not my combo.

I disagree on these points. I use to have 3.50 gears and a 3600 stall. The car actually improved it's 60' by going to the 2.75 gear and smaller stall (it stalls to 3000 n/a on the trans brake, just checked the other day when I popped an i/c pipe). My 60's went from 1.8s to 1.6s with the gear and stall change. Before the change I was not able to hook the power at all, but LVMS does not prep the track for the events I run. I also ditched my headers and went back to stock manifolds. The combination that I have now makes a really great street car and it's a lot of fun.

I'm expecting to run 10's next wed night since the track temps have dropped from the 100's at night to the low 70's at night. Tonight the DA is only 3100 at 11pm and it's 67 degrees out.

Maybe I should pull the dyno numbers out of my sig since they really seem to confuse the hell out of people. This same turbo setup managed 625 rwhp on a dynojet @ 13-14psi spinning the tires. This was with my stock motor and 6spd tranny. I'm pretty sure it was making close to 700 rwhp at 15psi be we could never get it to hook on the dyno or make 15psi on the dynojet.

SmokinHawk, if you are ever online I'd like to talk to you about your setup.
The reason I'm asking about the T88 is I don't want to swap if it's going to be a huge difference unless it's a huge gain in power (i'm willing to spray it too). This car gets drivin about 150 miles every week. I wish there was a turbo inbetween the 76 and the 88, I know there is an 80mm from ITS but i've been told the upgrade really isn't worth it.

P.S. to let you guys now what our track is like in summer a stock LS1 will run low 14s @ 98-101 mph it's a struggle to get them into the 13's without mods.

 

id like to know how the hell smoking was hitting 10psi/full boost at 2700rpms with a .96 T76?how is that possible in a stick?are we talked about at launch with a 2 step?

 

Zom, I would talk with Jose again.....he's the man when it comes to picking these hard combo's out. The PT88 is a slow spooler indeed.

 

The PTE88 with my 347 cubes, you dont even feel like your waiting for it to spool. The car is definatly more beastly down low then my old turbotech kit with the t76., might be the piping difference, or the gearing change.
but its not a bad turbo at all.
id tend to agree and try to push all that you can out of your current turbo, if you havent already. then upgrade.
Im no where near pushing my 88mm to the max yet, im actually just getting into the effeincy range, as im working on upping the fuel system and tuning. that turbo should put down 1000RWHP, i think i was about close to 700rwhp with my weight and trap.

i think my old T76 from turbotech (turbonetics) was just a 60 series turbo opened up to 76mm from what i was told. it had small parts so it spooled fast, i also had a cut out right after the dow pipe, so it spooled fast with my stick (thats just regualar spool, not on a 2 step)

 

how does that turbo compare to a T76GTS .96 a/r?

Sorry zombie dont mean to hijack your thread,im just fascinated cause i start to spool my turbo where smokin was hitting full boost.

 

The GTS uses the same compressor wheel, but much larger turbine wheel. Which means more flow for the GTS, but slower spool.

 

I apologize as I didn't know all your variables. Though, I'd still have to say try to max out your current combo. I've worked with alot of cars, even ones dealing with high altitude ( i missed that part on your car) and still think you could do better. It's great the car is doing what it is already ...but keep pushing it.

 

Actually, a GTQ vs. a GTS isn't that much larger. You're right, the comp wheel is the same, but on the turbine side it's 3.110/2.695 (ind/exd) vs. 3.200/3.690. So, the inducer is the only part of the wheel that is slightly bigger...while the exducer is actually smaller.

 

A GTQ is indeed 3.11 I/ 2.69E, but a GTS is 3.200 I/ 2.96E. Also what's not taken into account is wheel weight and trim. The GTS has a higher trim, so that means more flow, but also the wheel has a tip to tip height of about .5 taller which is quite a bit in terms of weight. Also if its on a TTI kit I suspect its an old T-netics unit, so its not a GTQ either. It will be a standard Q, which flows even less, but does spool quicker since its a 12 blade design. Keep in mind turbines will flow GREATLY different even though they can have the same I/E, just due to turbine tip height, blade count and pitch.

Jose

 

Yep....right on the money.

 

I am trying to max out this turbo but am running into issues getting it to go over 17psi consistantly. I have been able to hit 20psi in 3rd gear once, but I didn't feel any difference and my IATs went up. Does anyone know roughly the max boost for a T76 on a 370 cube motor?

My turbo also uses the Innovative R wheel which has a trim of 1.00 and Jose tells me it's quite heavy. I'm at a big disadvantage with having the turbo all the way at the back, but I'm trying to make up some of that difference by insulating my exhaust. I am either going to wrap it or just get it ceramic coated and be done with it. Luckily we have a coater here in town.

JZ 97 SS 1500, since you are in here and know about my setup, do you think it would be a worth while switch to go to an 88mm based unit or would it be too much for my setup to spool. A friend of mine who likes to fabricate have been considering doing a variable a/r experiment with a divided housing so that is the other idea that I have... more plumbing LOL

I've been going against the grain a bit since starting this project (back in the days when a rear mounted turbo couldn't possibly make boost). I'm kinda curious as to how far I can take it now. My goal with this setup is mid 10's and a 130mph trap speed. I should be getting really close to that next week. The car is an absolute blast to drive, especially from a highway roll with my gears.

I could always start spraying it I guess, that guarantees the same drivability and fun factor it is now.

 

gotcha....thought i was losing my mind.i was like "full boost @ 2700...W..T..F!"