the 3sgte head difference, 2nd. vs. 3rd. Options

[frosty]

Alrighty,

I'm looking to perform the 5s-gte motor build-up and I'm trying to decide which gen. gte head to go with. I know the 2nd gen had the tvis system and the 3rd didn't. I also read on some guys page months ago (and now I can't find it) that the 3rd was a better casting. To me that didn't matter if the head is getting ported and polished, but I believe he said the 3rd already had larger ports. (he had both heads side-by-side for visual aid) Mainly I noticed the difference in the 2nd and 3rd is that the 3rd came with a slightly better turbo and different compression ratios (probably a more aggressively tuned ecu?). I asume that this is really the main contributing factor to the 50ish hp increase.

I just want to know if there is any real advantage of one head over the other.

I see that alot of member on here swap using the 2nd gen motor and have great success with it. Esspecialy with the ct26 turbo. I pretty much want about 250 to 300 whp as a daily driver and see that it's done with the full 2nd gen. 3sgte.

If there is no real huge advantage of one head over the other then I would go with the 2ng gen. due to it's easier to find, parts are also easier to find, and the fact that it's cheaper than the 3rd.

[frosty]

Yeah, I figured I would get some answers that didn't pertain to my question. (that happens alot on this forums, any forum actually.) I guess when I said I wanted 250-300ish whp I should have said "for now". I really want 400 but that will require me dealing with traction issues right off the get-go since it would be my daily driver. Yes, I know I can get this whp level with a standard 3s-gte but why when if I had a 3s-gte I would increase it's displacement from 2.0 to 2.2 or more? I cut out that step. Also asking "why do it" in regards to making it seem like a wasteful idea is the same as asking those that turbo their 5s-fe the same question. Why do it if the 3s-gte can already do it? Because it's different. It makes it more exciting for me as I asume it's more exciting for those with 5s-fte's to have that instead of a 3s-gte. Am I not right?

I know what I'm getting into. I've been researching this set-up for awhile now. I don't want to start up an argument over "why do the 5s-gte". It's just about the same argument as with 5s-fte. I should've just posted a one-line "which gen head flows better".

gen3 540cc injectors: gen2 440cc injectors

gen3 Large lift more aggressive cams
gen3 Shim under bucket valve shims: gen2 Shim over bucket
gen3 different exhaust manifold stud placement
gen3 TB 60mm: gen2 TB 55mm

Injectors are not a problem since I would buy new ones right off the bat.
Cams wouldn't be changed at first, but would be down the road so no problem there.

I pretty much want about 250 to 300 whp as a daily driver and see that it's done with the full 2nd gen. 3sgte.

Ummm... 250-300whp is *easy* with a stock 2nd or 3rd gen motor. No need for a hybrid motor and all the headaches that come with it.

Heck, after a boost controller, water injection, 3" exhaust and intake, I should be in the 260-280whp range without any problems (with near stock reliability). Without the boost controller (just intake and 2.5" mandrel-bent exhaust) my car already has around 240whp. (see my sig, 3rd gen FWD motor swap)

-Charlie

Yeah, but how much more did you pay for the 3rd gen? If I can buy a 2nd gen for almost $1000 less, use it's head/ecu and achieve the same hp as you have, wouldn't mine be a better deal?

The gen III flows more air - no question about it.

That's not what I read.

Actually the Gen II head flows more air on a flowbench.
It has MUCH larger ports than a Gen III.

The whole engine package stock however, probably Gen III.

With that said, the Gen III has a better INTAKE cam. The exhaust cam is the same specs.
I don't know which intake man flows better. Probably with the TVIS removed the gen II would, maybe even with the TVIS. It does have more overall volume in the runners I believe.

This answer is actually what I've found when looking for head differences.

I have read that having the tvis is good for a little more than 300 hp, but beyond that (400 hp or more) it's better to do away with it because at that piont it begins to hinder the airflow.

why do you want a 5s-gte? you can get 250-300hp with just a normal 3sgte.

already answered above

2nd gen USDM engine and ecu
stock fuel system
3" turbo back
2 1/2" IC piping to massive FMIC
Apexi AVC-R Electronic BC
a stevetech throttle body inlet 2 1/2" then port matched to TB
Tial 38mm external WG
GT2871r turbo w/ T25 exhaust housing and GT28 compressor housing
Forge Motorsports recirculating BOV

Everything else is basically stock.. I have the TVIS actuator hooked up to manifold so as soon as I get into positive pressure the plates open..

Anyway I put down on the dyno 287whp .. slightly over 290ft/lb's on 14PSI.. if I had more fuel I would've hit 300.. oh well.. I daily drive the **** out of it.. I been hammering it through this snow storm..

Anywho.. hope that gives you some idea's.

Appreciate it.

*my edit

Besides, I'm still in the research phase. I don't want to spend a dime until I know the full path I'm gonna go. Who knows, before this is over I might just go with a 3s-gte swap instead. I just like the thought of a 5s-gte better right now.

This post has been edited by frosty: Feb 16, 2007 - 11:54 AM

[phattyduck]

I pretty much want about 250 to 300 whp as a daily driver and see that it's done with the full 2nd gen. 3sgte.

Ummm... 250-300whp is *easy* with a stock 2nd or 3rd gen motor. No need for a hybrid motor and all the headaches that come with it.

Heck, after a boost controller, water injection, 3" exhaust and intake, I should be in the 260-280whp range without any problems (with near stock reliability). Without the boost controller (just intake and 2.5" mandrel-bent exhaust) my car already has around 240whp. (see my sig, 3rd gen FWD motor swap)

-Charlie

Yeah, but how much more did you pay for the 3rd gen? If I can buy a 2nd gen for almost $1000 less, use it's head/ecu and achieve the same hp as you have, wouldn't mine be a better deal?

If you read my post, you would see that I said "2nd or 3rd gen". For my goals (really, just a reliable 250-300whp), the 3rd gen motor was/is perfect. A 2nd gen motor can be brought to the same power level with similar reliability with the right modifications.

All that said, my opinion is this:
Do the 3s-gte swap. Get it up and running and get your 250-300whp. Enjoy it for a while and see if you like it. If you need more power, you can then build a 5s-gte. In the end, it should be about the same amount of money (the only extra cost is the 3s-gte block), and you can stop at any time if you are happy with the power level, or maybe unhappy with the traction.

-Charlie

[JesterDC]

If you read my post, you would see that I said "2nd or 3rd gen". For my goals (really, just a reliable 250-300whp), the 3rd gen motor was/is perfect. A 2nd gen motor can be brought to the same power level with similar reliability with the right modifications.

All that said, my opinion is this:
Do the 3s-gte swap. Get it up and running and get your 250-300whp. Enjoy it for a while and see if you like it. If you need more power, you can then build a 5s-gte. In the end, it should be about the same amount of money (the only extra cost is the 3s-gte block), and you can stop at any time if you are happy with the power level, or maybe unhappy with the traction.

-Charlie

He can do what ever he wants to, and if he wants to tinker around with a 5SGTE hybrid good for him. Also, it's common knowledge that the 5SGTE is a much stronger engine than the 3SGTE and has much more potential for massive power. I saw a MR2 in Sport Compact Car a couple months ago that had a 5SGTE with a 2-stage fuel system pushing over 750whp, the Top Secret 3SGTE supra is barely pushing 700whp and there was much more development put into that car.

And to the 5SGTE guy, almost all flow benches will report better flow for bigger ports, but if the ports are to big for the engine to fill with air then you'll have turbulence->loss of torque->loss of hp, just fyi