Trying to decide on the backside for my GT40r.

[Flateric]

My old turbonetics along with my HKS electronics have been stolen so I am in the process of redoing things.

I am down to having to make a decision on what backside to get for the GT40r I have settled on for my MKIII/2jz setup, .64, .83, 1.06.

1.06 is way to big I think, affecting my spool and giving me huge power potential but much smaller power band as I understand it (spools too late).

.83 seems to from what I understand gives me great power potential and only slightly less spool response than the .64.

.64 great spool but a little limiting in the potential power over all.

The rest of the supporting parts that are relevant are,

-1000cc injectors (may switch to 800cc, not totally sure yet, feel free to tell me what you think here also please).
- Vielside Intake
- 100mm throttle body
- Intercooler etc to match.
- 3" turbo back greaddy exhaust
- Engine managment (undecided after my HKS setup was stolen)

I think that should be all the info to help me make this decision. Thanks for any suggestions any of you may have.

 

[86_sports_1jz]

how much power do you plan on making?

 

[Bigzavs]

id suggest the .83 A/R, ya you dont have the lightning spool of the .64 a/r, but youll pull much better up in the high rpms with the .83 than you would with the .64

 

[tissimo]

1.06, get some hks 272s, port the head and rev to 9k

 

[Flateric]

For just ripping around the city and having fun I'd like to sit around the 550-600 mark comfortably.

When I'm at the strip (my brother and I are very competitive and he's a nissan 300zx guy) I'd like to have room to turn it up from "stun" to "kill" so to speak.

Any thoughts on the injectors? Or engine management?

 

[di_rosa]

i didn't see a 0.64 a/r for the exhaust housing anywhere? the smallest i saw was 0.85, and that's what i got

 

[86_sports_1jz]

For just ripping around the city and having fun I'd like to sit around the 550-600 mark comfortably.

When I'm at the strip (my brother and I are very competitive and he's a nissan 300zx guy) I'd like to have room to turn it up from "stun" to "kill" so to speak.

Any thoughts on the injectors? Or engine management?

i would probably go with the .84 or .85 to give you some space to "turn it up" at the track. as for injectors and ems, i would get at least a set of 720cc injectors, then for the ems there is stinger, power fc, aem ems, etc.

 

[annoyingrob]

.83 all the way. You're still going to hit full boost 3600-3800rpm

and by .83, I assume you mean .83 T4, not .83 T3 (I don't think they even make the GT40R in a t3 flange, but I figured I would mention it.)

 

[RacerXJ220]

If you want to use that turbo fully, start with the 1.06, then go down if you don't like it.

You did say GT40R. My setup right there.

 

[Flateric]

If you want to use that turbo fully, start with the 1.06, then go down if you don't like it.

You did say GT40R. My setup right there.

How much later on does the spool come for the 1.06?

And I hit a major snag this evening. You see I have essentially been rebuilding this car after painting it over the winter (and then again over the summer after it only lasted 3 hours before being totally vandalized by my ex's new boyfrind whom assumes since we talked on the phone we must be screwing also, IDIOT.....anwyas.....it was all perfect for about 3 hours before he got to it and I had to do it all again.)

Well I am having a clearance issue with my huge intake and my brake booster (I think thats what it is anyways, the HUGE ugly cylinder mounted on the firewall. My vielside intake it actually just touching the damn thing which is of course not a good thing.

What are the internals of that thing all about. Can I bash about a quarter of a golf balls radius into it without killing, comprimising it? Can I swap this for a slightly smaller/different/anything that'll give me that 1/2" of space I need?

I could also cut a 1/4 golfball sized radius out of the intake, flip the concave piece that results and weld it back into the same hole in a convex direction to give me the clearance, but I would like to leave that as a last option. (I am pretty decent at welding aluminium and have the equipment to do so, so this is not as frankenstienish as it may sound)

Frustrating.............so close, so damn close it's one of those things that when you look at it you think, hold on, thats gotta work with a little adjusting! LOL....nope!

 

[RacerXJ220]

If you're going with a larger intake manifold, sounds like you're going to want to use this turbo to all the way. The 1.06 will free up all the power you can make from this turbo.

You can use one from a toyota pickup truck, not sure which model just go check them out and compare.

 

[annoyingrob]

The intake manifold is designed for a right hand drive car, with the brake booster on the other side. It's been discussed over and over on this forum.

 

[porsches4lunch]

If what you really want is response then for sure go with the .83 housing. It is a divided T4 turbine which will give you excellent power and good spool up.

 

[Flateric]

If what you really want is response then for sure go with the .83 housing. It is a divided T4 turbine which will give you excellent power and good spool up.

Well, I put my money down and ordered it up yesterday and thats the exact setup I went for. Now I'm just waiting on the 1000cc injectors and I still gotta pick a exhaust header and engine management.

I'm leaning towards AEM and still have no idea on what header I'm gonna get. It's of course gotta fit in the MKIII, I'm not sure that all 2jz headers will fit in the MKIII. What are you guys running?

 

[porsches4lunch]

Well, I put my money down and ordered it up yesterday and thats the exact setup I went for. Now I'm just waiting on the 1000cc injectors and I still gotta pick a exhaust header and engine management.

I'm leaning towards AEM and still have no idea on what header I'm gonna get. It's of course gotta fit in the MKIII, I'm not sure that all 2jz headers will fit in the MKIII. What are you guys running?

We have a customer with a MKIV (cams, inj, AEM ) that we did a PT72 Custom with a .81 A/R S trim wheel. He is VERY happy with the response and power (he has made over 600 RWHP with it. Garrett rates the GT4088R up to 700 HP and i believe them. They typically UNDER rate their turbos. For instance, they rate the GT35R as up to 600 HP and there are folks that have made more than that. For a daily driver i would not go beyond a GT42 with a smaller back housing like a .81 S Trim. Once you go .96 A/R on the turbine and above on the 2JZ you notice a considerable amount of lag on the street. For a track car or a Dyno car it's a completely different story. Most of the customers we have with 2JZ are running the AEM and they love it. There seems to be more folks that tune it than others.

 

[figgie]

For a daily driver i would not go beyond a GT42 with a smaller back housing like a .81 S Trim.

First off, Why would you use such a monster turbo with that teeny tiny a housing? Can you say SURGE MONSTER?

anyway. the smallest AR that Garrett has for the GT42 is a 1.01 and the biggest is 1.44.


Size the turbo to the application not the A/R to the application.

 

[RacerXJ220]

Size the turbo to the application not the A/R to the application.

+1

 

[porsches4lunch]

First off, Why would you use such a monster turbo with that teeny tiny a housing? Can you say SURGE MONSTER?

anyway. the smallest AR that Garrett has for the GT42 is a 1.01 and the biggest is 1.44.


Size the turbo to the application not the A/R to the application.

UMMMM "Custom" built turbo. BTW, we make turbos for 7second cars,and in fact the world record holder two rotor car, so unless you are running sixes in the quarter????

 

[porsches4lunch]

First off, Why would you use such a monster turbo with that teeny tiny a housing? Can you say SURGE MONSTER?

anyway. the smallest AR that Garrett has for the GT42 is a 1.01 and the biggest is 1.44.


Size the turbo to the application not the A/R to the application.

.81 A/R S trim T4 turbine is tiny to you? Ok, i have seen several folks use a T3 .82 A/R "that comes standard on a GT35R" and they are very happy with it. In fact somebody on this board just make 600 RWHP on a 1JZ with a T3 .82 A/R Housing. BTW, i have a better one for you, build the Turbo for the car

 

[figgie]

UMMMM "Custom" built turbo. BTW, we make turbos for 7second cars,and in fact the world record holder two rotor car, so unless you are running sixes in the quarter????

7 second cars?

from Miami? What are you doing, throwing them off the Key Biscayne bridge into the bay as that is about the highest point you got.

Let me take one guess. Double Rotories from florida...........inline with what I remember.

Seems like Garrett knows nothing about their own turbo's. I should have known!

81 A/R S trim T4 turbine is tiny to you? Ok, i have seen several folks use a T3 .82 A/R "that comes standard on a GT35R" and they are very happy with it. In fact somebody on this board just make 600 RWHP on a 1JZ with a T3 .82 A/R Housing. BTW, i have a better one for you, build the Turbo for the car

and this tell me what? That tuners such as yourself have propagated that bullshit of using choke inducing A/R's to achieve quick spool? Last I checked, a GT35r is not a GT42. T3, T4. Glad you know the mounting pattern but what does this have to do with turbine flow capacity?

Let me guess, you also like to use cool words like "back" pressure and other words that really don't exist to communicate.


Build turbo for the car... wow! Stephen Hawking would be in awe with such a well thought out post!