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L28ET/GT35R Characteristics


thehelix112

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Guys,

 

Been getting a few PMs about this so figured I'd post a thread.

 

I know Tony has already reported that JeffP gets full boost by 3500ish on his stroker L. So I would expect to be getting full boost somewhere between 3700 and 4000 on a standard L28ET, with appropriate wastegate control/exhaust of course.

 

The GT35R is a nice size for the L28ET depending on what you want to do with it. If you want a street car that will pull from almost idle this isn't the combination for you. If you want a car you can toodle around in off boost but has plenty of power available up higher then its perfect.

 

FWIW with a decent wastegate spring and 3" no muffler exhaust boost hits hard around 3500 (no tacho/log so I'm just guessing) and spun up the wheels in 4th (in the dry, with a locker, at 65mph). The new garrett BB turbos come on VERY fast. I know track racers who go oversize turbine housings and throttle dependent boost limits just so they don't fry the tyres.

 

If you can afford it, and the systems to run it (460cc injectors at 48psi are only good to around 20psi - just getting cooking on this turbo), I say go for it.

 

Dave

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I'm still sorting it out properly busmn280, no dyno sheets as yet. Engine is a stock L28ET (F54/P90). Have a look at JeffP's posts for a dyno sheet of one on a stroker. Then push the graph a little more to the right and that'd be about it for a std L28, at a blind guess. :) Will keep you informed.

 

Dave

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S15_200SXetcetc,

 

Yep, tis a VL.

 

busnm280,

 

My autronic is a SMC. Base piece of crap. Single coil ignition using #1 spark plug reference (ewww!) and a custom hall-effect dizzy. Very simple, but works ok.

 

ZuL8r,

 

0.82

 

240hoke,

 

1400USD? Joking. Mate just got one ex-USA for USD1250. Must be cheaper over there than that?

 

Dave

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Guest 280ZForce

thehelix112 - I'm also looking into changing into a gt35r from my full t4...what specs should i be looking at? i also have a stock l28et motor.

 

thanx in advance.

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S15_200SXetcetc' date='

 

Yep, tis a VL.

 

busnm280,

 

My autronic is a SMC. Base piece of crap. Single coil ignition using #1 spark plug reference (ewww!) and a custom hall-effect dizzy. Very simple, but works ok.

 

ZuL8r,

 

0.82

 

240hoke,

 

1400USD? Joking. Mate just got one ex-USA for USD1250. Must be cheaper over there than that?

 

Dave[/quote']

 

All you guys that are after a new GT35R, make contact with James Thagard on this forum, he did me a great deal on mine, and i am sure he will look after other fellow HybridZ members.

 

James Thagard turbo@speedshopthagard.com

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Good info Dave, thanks. My take on the GT35R now is that the .82 turbine A/R is about right for a stockish L28 while a cross flow head three liter equivalent* would be the 1.06?

 

As long as you don't want to pull stumps @ 2000 RPM :)

 

*RB30ET, VG30ET, VG30DET.

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280ZForce,

 

The GT35R only comes in 3 specs representing different A/R turbine housings. 0.63, 0.82 and 1.06.

 

The choice is up to you but I would say that 0.63 would choke an L28 before 7000, 0.82 comes on nicely around 3500ish, while a 1.06 will let you max out the compressor and take around another 1000rpm to come on - from what I hear, never done it myself.

 

Richard,

 

You could use either I would think. A friend runs the 1.06 on an SR20 with some angry cams and makes full boost (26psi) by 4800.

 

Dave

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Hi guys, I have just looked at your specs and I dont have as yet the complete dyno sheet on the turbo. I can tell you a few things though, you DONT want to run the .82 A/R exhaust turbine housing on the 35R turbo. The spool comes on to late for my taste. I tested that and was getting right around 3500-3600 and by 3700 could get the response I wanted. I did go with the .63 A/R housing and that is working well. Killing the power @ 7K well if you have your exhaust system good before with a 3" mandrel system you should be just fine.

I tested my system back pressure and never reached crossover so if you do have a good exhaust then you will be fine.

The GT housing is much better suited to run higher numbers then the older turbo's, and they now have som good vband attachments to the back of the turbo.

I have not run my car up past 5K because the MSD coil I found out, only after I went to dyno the car is a piecs of crap and arching out. BTW that is the second coil I have had on the car from them and that was about 15K worth of driving. I placed a call to them regaring this issue and the cust service guy said it was my car creating the problem, which is total crap. I wont run another coil from them, I think they are crap, and I know of a number of others that have had the same results as I have had, so THEY ARE DONE! I will still keep the 6A.

The turbo starts making boost in my car @ 2500 rpms, and I am looking at spool response right at 3K but I need to test some more. I kept the car cool until I got it tuned, and that blew up in my fact last test. Not to worry, things are well at hand, but being christmas and all I think the first of the year will be when it gets it's tune verified and I get the dyno numbers.

I can tell you one thing though, @ 8psi of boost 5K rpm's the engine made 270hp and 290foot pounds of torque on pump gas. So this thing is going to really be a monster.

I am very happy with the response of the turbo, it is very close to the TO4E I was running, so lets just see what the final results are.

Dont worry about the .63 housing, go that way if you can get the turbo configured that way. When I got my turbo the .63 housing was not offered, then a year later and $600.00 for the part jethot and some special work I had what I wanted. Anyway hope that helps you out.

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You're running the 0.63 on a 3.0L, and you've never revved it above 5000 and you're telling us to get them? Are you SURE its not going to die over 7000rpm? I remain to be convinced I'm sorry.

 

Edit: I suppose for a std engine the 0.63 would be great: wider power band as most L28s get max power around 5600 unless they've got some work/camming. I want more power than that, and later on so I'm happy to sacrifise some low down response.

 

3500-3700 is perfect for me, revs never drop anywhere near that on the track, and i can drive it off boost happy as larry. Depends what you want to use the car for I suppose.

 

We'll have to compare dyno graphs (apples and oranges given you've got a stroker) but anyway. :) What cam are you running jeff?

 

Dave

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