best turbos and superchargers sc400

[feztallica]

i have an sc400 and i was wondering what the best turbo and superchargers were for maximun power output. if you could put the exact model numbers and the sites i can find them at i will worship you. i'm new at this and i thank you all in advance for the help.

 

[Lextreme II]

Can you define "Best" for us. If we know your difinition of "best" then its alot easier for us to help you.

 

[cowboy bebop]

Maximum HP output on the 1uz has as much to do with proper preparation as it has to do with turbo selection. Things to remember with dealign with the 1uz:

*You must fortify the block to handle the HP your'e seeking. Meaning hardparts like rods, pistons, bearings, studs, ect. Engine builder prep counts for as much as parts selection. My engine builder has put out over 20 2jz-gte motors alone, a most of which see 800rwhp on up over 1000rwhp.

* For maximum HP production, the 1uz heads are not the best platform around. However, if stuck with them, a careful port / polish would helo greatly. Along with replacing the small 28mm exhaust valve with 1mm or 2mm oversized. Cams would benifit as much or more than any other headwork, since the stock cams are meant more for manners, than brawling. Valve springs with a stiffer seat and nose pressure would benifit greatly, and add a layer of protection.

But in responce to your original question, the short answer is twin GT35R turbos.

Eric

 

[dass]

I would think that twin gt35 would give you a major compressor surge problems .

 

[cowboy bebop]

What is the base of that? Because on a 3sgte, 2.0L 9:1 CR, it's considered to be one of the larger street turbos, with full boost past 4300 rpm. FWIW, a 61mm turbo with a .58 a/r surges at half throttle on a 3L motor. This is cured by switching to a .81 or .96 a/r.

THanks Dass,

Eric

 

[Pro]

twin GT30Rs on a stock engine would be my pick with 35mm ID manifold pipes.

once you start playing with BIG boost, cams etc i would look to a pair of GT35Rs and minimum 2.5in pipes to feed it from each exhaust port.

 

[dass]

2 x Gt3540 60lb = 120lb compressor flow.

Have run 2x gt3040 on a 2jzgte . check the maps.

 

[martydaman1]

Pro.......2.5in pipes to feed each exhaust port? what are you talking about that is insanely huge.

 

[dass]

I think he means 2.5" to feed the turbos.

 

[WICKED SC400R]

2 x Gt3540 60lb = 120lb compressor flow.

Have run 2x gt3040 on a 2jzgte . check the maps.

actually 2JZGTE has run twin 3240's...

 

[dass]

It two would have had bad compressor surge as well ,I have also driven a supra
with twin 3540's .so what is your point?????????

 

[martydaman1]

I am not sure what setup bebop is going to be running, but I have done all of the calculations and the engine I am building will flow 127lbs/m at top end, and there will would be no surge with thoughs turbos anywhere on the map, my engine will be a 4.5 liter that revs to about 9000rpm with some head work. there are also a ton of mustang guys running a set of these on their 4.6 liter engines, and thoughs are push rod engines with low VE's when compared to our engines. So I do not think thoughs turbos would be any problem at all. I was also looking at a set of gt4088r's I have done all the calculations and there would be no surging wiht thoughs, they would put me in the 800-1400hp range, also ball bearing which would not make them too laggy.

 

[Pro]

no, i mean 8x runs of 2.5in.

insanely huge - yes. to even consider using those turbos on a 4.0, you need absolutley minimal "back" pressure (god i hate that term), along with many other mods (big cams, big boost).

when they all come together at the flange, gas speed increases and aids spool up - like putting a turbo just after an expansion pipe on a two stroke dirt bike.

there is sound theory and practise in doing this. have a look at all the turbo small blocks doing the rounds - all minimum 2.5in pipes. i know of a drag car that had to "settle" for 2.25in pipes because there wasn't enough room for 4x75mm (!) on either side.

we're talking extreme engine development here. otherwise, for a good streetable combo i would use the 35mmID pipes like i mentioned.

 

[cowboy bebop]

Remember, that you still have to fill those insanely huge runners with exhaust pressure to be able to spin the turbo, and that adds to the rpm in which you hit full boost. RPS "big torque" manifolds ran a stepped runners, and while extreme top end HP, and the final dyno number was larger, it still added between 300 and 500 rpm to the spool time.

35mmID runners would be more than enough and at that point they they become a restriction, there's a lot more holding back HP than runner diameter.

Eric

 

[martydaman1]

I think I am going to have to agree with comboy on this one, as long as the runners are not a restriction, you want as small an ID as you can. This will yeild much faster spool times due to the increased exhaust gas velocities. Also, simply running larger turbos will reduce exhaust gas back pressure in and of itself more than the smaller runners will. This way you have somewhat mid sized runners with larger turbos, and you have the high exhaust gas velocities needed to spool up the larger turbo, and you might have the same net back pressure as someone running over sized pipes on a tiny turbo.

 

[Pro]

for a street combo - yes i agree wholeheartedly as i mentioned.

but for an outright race application, bigger is better. period. the turbo itself is a bottleneck, so all the gas has to come together anyway.

 

[WICKED SC400R]

no, i mean 8x runs of 2.5in.

insanely huge - yes. to even consider using those turbos on a 4.0, you need absolutley minimal "back" pressure (god i hate that term), along with many other mods (big cams, big boost).

when they all come together at the flange, gas speed increases and aids spool up - like putting a turbo just after an expansion pipe on a two stroke dirt bike.



there is sound theory and practise in doing this. have a look at all the turbo small blocks doing the rounds - all minimum 2.5in pipes. i know of a drag car that had to "settle" for 2.25in pipes because there wasn't enough room for 4x75mm (!) on either side.

we're talking extreme engine development here. otherwise, for a good streetable combo i would use the 35mmID pipes like i mentioned.

an expansion pipe would decrease speed of the air...and cool off the charge... you don't want either on a turbo mani...

My friend Dana Westover at Virtual Works Racing had some 1.5" pipes on his original exhaust manifold on his 1400RWHP Supra and when he changed his setup he made a new manifold that was 2.25" piping thinking the higher hp engine needed nore flow. He lost over 300RWHP. US USING 2.5" PIPE WOULD BE OVERKILL X 100!!. Unless you have some pro-stock 2500hp car I would not recommend going over 1.75"... I am going 1.5" on a cast style mani most likely... COWBOY IS RIGHT!

 

[martydaman1]

Thank you for bringing some sanity back to the forum

 

[cribbj]

I don't think there was anything insane about Pro's post. He was first speaking in terms of "extreme" engine development, and then qualified it by recommending the 35mm (1 3/8") runners for a street setup. That seems to be right in line with the rest of the discussion.

For certain turbocharged applications, where spooling isn't a consideration, but turbocharger efficiency and reduction of exhaust back pressure are, you'll see bigger runners and A/R's on the turbines. The old CanAm and Indy racers were setup this way, and turbocharged industrial engines still are.

Having said this, even MacInnes didn't recommend sizing the runners any larger than the exhaust ports.

John

 

[martydaman1]

I do not think there is any amout of horsepower that could be pushed through the 1uz heads that could warrant 2.5 inch ID exhaust runners.