GT40 = how much lag to expect?

[sho_tyme_psi]

I'm thinking of getting a new gt40 non-ballbearing for my car and wondering how much lag I could expect. I was expecting full boost by 5000RPM, the specs are
Turbine:
-Wheel: 77mm with 73 trim
-Housing A/R: .94

Compressor:
Wheel: 82mm with 50 trim
Housing A/R: .58

I know .94 exhaust will be a bit laggy but my comp. is 8.5:1 and I will be spraying 75-100hp shot when racing. I don't need any he said its to big and why would you want that, i need answers from people with them or a gt42 feedback. but I have my big 60-1 sold so I'm chipping in some more money and going to buy this. all feedback greatly thanked.

 

[94Jettameowpsst]

The gt42 thats going to be on my 3000gt im expecting to spool around 5000 but its also a bb turbo, so expect a bit higher than that considering you have the same hotside that i do.
Edit, your spool should be around 5k, my turbine ar is 1.15

 

[98talonAWD]

a GT40 non-ballbearing is a dog.. i would say atleast 25psi around 5500 at the lowest on the non-ball bearing and that would be on a higher compression stroker motor.

the 3.0L vr4 would probably spool a gt42R (depending on the size of the compressor wheel, 94mm, 102mm).. around 6000 i would estimate. when you pick turbos of these sizes you have to think on the worse case side of the time. if you think it will spool by 5K, you better add a little bit in, because it probably wont do what you think it will.

 

[sho_tyme_psi]

Well they claim with the GT series its alot faster than the old t series on spool, as far as motor I'm staying with my 2.0 (.040) and the comp is up to bout 8.5:1. but for the price I can pic this up for with a warranty from Garrett its hard to pass up. I will also be turning the motor kinda hard so spool should be fine once I get through first gear. I just hope it fits ok, I have a fluidyne civic radiator in my car(half size) so that has free up alot room.
keep the comments coming good or bad ill take them all.

 

[98talonAWD]

if your going to do it... just get a ball bearing. you wont be happy with the spool time or throttle response between 1-2 shifts on a non-ball bearing GT40... remember...they made it ball bearing for a reason. most people didnt or couldnt use the gt40 until the 40R came out. in my opinion i would talk with garrett and see if you could get there new GT4067R. the compressor wheel is a little smaller than the GT4088R, but will only aid in spool up and is good for 700hp or more. if your not going to push that hp range, why get a turbo thats made for 800 when you arent gonna make 600?

its a lot more money for the BB turbo, but its well worth every penny. and anybody that says it isnt worth it, hasnt gone for a ride in a well tuned big turbo dsm. you would probably have to spool the GT40 non-ball bearing between 1st and 2nd again, just to get it going. and would only makre around 10-15psi in first at a max.

My Innovative T67 dual-BB GTQ trim turbo doesnt have to spool again between shifts and i have 7.5:1 compression on the 2.3L stroker. pretty close to the same size as a GT40R turbo. and i love this turbo.

 

[1fastlaser]

at 35r will do the job over and over again....gt40s are nice...but a .96 a/r is gonna suck.... i wouldnt go much bigger the a .84 a/r.I would get a gt40....but then you gotta go into things.....ok a gt40 that thing wont like it till your pushing it hard....now you need big injectors 1000 1600s.management aem....3.5 4.0 bar map.....the list will go and go and go......it always does it,it will never fail.You get to the point where you change one thing,and then you gotta change 15 things to make the one thing work

 

[sunflashx]

The .95 AR turbine housing is divided, and not comparable to a open housings ar. From what I've heard it's more comparable to the .68 AT T4 undivided housing.

PTE sells a "GT4067R".

 

[sho_tyme_psi]

Well as far as supporting mods i think I have them all, 1000RC's, aeromotive fuelsetup, intake, and motor. all I'm short is management. I'm going to prom with fuel control for now till spring and ill get my aem ems. I'm just tired of the damn thing not running and need it back together. As far as spool as long as it runs decent on street I have 2step and can spray past the lag when racing. and on top that I'm short a turbo now and dint have 1800-2500 for a BB turbo now, none the less I'm set on doing it and hope to post up bout how it runs by the first of the year.

 

[93AWDTalon1]

the 3.0L vr4 would probably spool a gt42R (depending on the size of the compressor wheel, 94mm, 102mm).. around 6000 i would estimate.

I just wanted to add ams's EVO (current world's fastest evo) uses a GT42R and gets full boost with it's 2.0L by 6k

 

[98talonAWD]

good... remember what i said, always go too high. dont say it will get full boost by 5K, when in reality it probably wont. if it spools sooner... be glad.

 

[bluegs-t]

get a bb center cartridge with a split tangenal exhaust housing. then, have AMS build you an exhaust manifold like the one that they have on their Evo. they get full boost with a GT42R at 5000rpm, straight from Martin Musial's mouth on teamnabr.

 

[JessesTalon]

2.0 L will take FOREVER to spool that 40R unless your car is a track only car (with that nitrous to spool it up) you will NOT like driving around town with a 40R..

even the 35R's on STi's don't spool up quick and they are 2.5L

I wouldn't recommend doing more than a 30 or 35R on a 2.0L

my buddy did 30R on his EVO (i know i know) and he made 460whp on race gas, 360 on pump...

and that shit spools pretty good, he maxed out the 30r though... he went 35r now i dont think he has had it dyno tuned yet

 

[sho_tyme_psi]

I am going with it regardless, I don't need fast boost on the street all thats good for is layer fee's and points on your license. I am wanting to make some high hp numbers and I cant do that with a smaller turbo,as far as manifold I have one lined up to be built this spring. Between 2step and brakeboosting if I need the power I'm sure i can find it, maybe not in first or even second but my car has a few more gears to catch people with. As for the 42R thats a great plan maybe next fall but due to some recent events I spent my turbo/rim money to help the fam. I would still like to get so replies from people that have these or bigger turbos. Thanks again for all the replies.

 

[94Jettameowpsst]

I guess i should have said my friends sr20's 240 builds 10psi by 5200 on his non bb gt40....it sucks, and he regrets not buying the bb center section, but it does pull retarded hard up to 9k so, its all up to you.
Friend's civic that was built by Hybrid Dynamics in Youngwood PA, b18 12psi pump gas, 396whp gt40 It will make power

 

[JohnTSI]

Lag is very overrated, that is all I have to say. If you worry about lag you are not worried about going fast.

 

[sho_tyme_psi]

JohnTSI thanks for the reply. I realize it wont have neck snapping low end I don't need that. I'm looking more for mid-top end power. As long as it runs low end and ill be happy. I have a billet bottom end and plan on turning it hard when i need to but as far as commuting around I don't need fast spool.(I have grown out of my light to light racing) As long as I'm getting into the boost from 5-5600rpms I'm fine with this. Only thing scares me about this is fitting this in the car.

 

[XakEp]

I have the GT40 on my 4g64 and it spools around 4500 rpms. And its not like a light switch, its a nice linear curve. I have plenty of supporting mods too.

Its not bad at all.

 

[JohnTSI]

With nitrous on a 2.0 your GT40 shouldn't have much of a problem, look at it like this. Even when I short shift the car it never falls below 5500. You will be just fine, on the street you can downshift in most situations. I wouldn't put it on a car running less than 9k RPMs on a 2.0L.

 

[sunflashx]

People should be aware that there's probably like 5 different GT40's possibly being discussed here.

There'e the 56 trim "GT40" compressor that comes in the FP3065, FP3565, SCM61, SC61, 35R, etc. turbos, then there's the new 88mm 52 trim and a 88mm 54 trim GT40R aka GT4088R. Both are technically a GT4088R based on Garretts naming scheme.

The GT4067R is a PTE build that has the "GT40R" hot side paired with a compressor that I have heard called a T67, GT67, t04r, and what FP told me came in a FP3575.

The original post notes a 82mm 50 trim "gt40". I have no idea what that one is.

 

[JohnTSI]

I am very much aware of what turbo he is talking about.

 

[sho_tyme_psi]

Well as usual the guy that was going to buy my turbo backed out but I have decided due to this thread I'm going to go ahead and buy it when my 401k check comes so I can put it on and relay the results to you this spring. As far as the GT40 size I thought I gave most all the specs it could be other than it is a T4 flange. I ordered 10ft 4" exhaust and going to order 2 bends today to start the exhaust next week. But due to all the snow I think my weekend will be tied up with alcohol, friends, and snowmobiles. but thanks to all for the replies and everyone have a safe and warm weekend.

 

[Boost Lee]

You will be happy with the GT40. The few people I have seen that were not satisfied, had unrealistic expectations. A friend of mine is using a standard GT42 on his 9.0:1 / 2.0L - Unfortunately I don't have any details other than how much power he put down. Feel free to chime in Ryan, Joey.

For reference here is AMS' GT42R 2.0L sheet -

You must be logged in to view this image or video.

Edit: I remember you now, the 4" exhaust guy.