our turbo vs 87 supra turbo

crappyrice · Post by **crappyrice** » Sun Sep 11, 2005 4:19 am

ok first of all i have a 97 legacy turbo, with auto trans. couple of questions

its said that our cars wastegate open at about 8 psi, and are esily caplable of over 14 psi, i need more infoo on that.

secondly about that supra.
a person has one and its twin turbo i believe, and they actually have a boost conetroller and they said they were running 4 psi. and when he was running it i was there outside the car, and his turbo is really loud, in a good way. plus he has a blow off valve so it sounds amazing. anyways i was just wondering how come his turbo setup seems to be stronger, is it casue ours is 4wd, or is his turbo setup actually stronger, even though it only pumping 4 psi.

one last question is that 4 psi constant to the engine right not the peak at which the wastegate opens, so i am wondering if our ewastegate opens at around 8 thats casue of th e pressure buildup, so when its actually open how much boost are we constantly getting. and do we not get that noise casue we have recirculation valve, and can we switch that with a blow off valve, an d how much would that coast.

my last question is that qas prices are too much, is there any way to decrease oto e boost or just kill it temporarly, without taking the turbo ou, like we need fuel economy most of the time to get to work and back, but we also like to have fun soometimes, with as much boos as possible, i know a boost controller can help incerase boost, but can anything help deccrease it too?

my last question is which car would win in a race.my stiock legacy, or his supra with boost controller, and bigger exaust?
LOL

Suzie-Q · Post by **Suzie-Q** » Sun Sep 11, 2005 8:09 am

holy hell. short, complete sentences are good.

vrg3 · Post by **vrg3** » Sun Sep 11, 2005 3:07 pm

Hehehehe...

Welcome to Legacy Central.

Some of your questions have already been discussed on the board. You'll find that you can learn a lot by just searching through old posts here.

When you do post to discuss new stuff, you'll also find that you usually can get more people to read it and help you out if you take a little time to write as clearly as you can.

That 87 Supra is not a twin turbo. He has the 3-liter 7MGTE engine with a single Toyota CT26 turbo.

His turbo should be making about 6 or 7 psi at peak. If he's really only getting 4 psi, something's wrong.

The reason his car seems stronger than yours is that it is stronger than yours. The cars' weights are similar, but his engine's bigger, with a more efficient turbo and a decent intercooler. From the factory the 7MGTE is rated at 200 horsepower; your EJ22T is rated at 160 horsepower. In a straight-line race, he should be able to beat you pretty easily.

Binford · Post by **Binford** » Sun Sep 11, 2005 7:50 pm

Actually. the turbo Supra has more like 220 hp, if I remember correctly. The factory weight rating is 3500 lbs, again, if I remember correctly. The 5.9L V8 powered Supra sitting in my driveway weighed in at around 2800 lbs on a truck scale, and is estimated at 475 hp.

91White-T · Post by **91White-T** » Sun Sep 11, 2005 7:57 pm

Its not all about the pressure ratio... 5psi from a baby turbo like a VF11 is NOT the same amount of air as 5psi from a bigger turbo, like say a 18g.

crappyrice · Post by **crappyrice** » Mon Sep 12, 2005 1:37 am

well ur both kinda wrong the 87 supra was rated at 230 hp and 243 torque, much more than ours i already know that, but i was wondering if his is biger than ours, cause how come he was running 4 and we run like 8, but his u can actually hear from outside thae car , like very loudly.

also any answers on the boost controll quesstion i asked,?

stipro · Post by **stipro** » Mon Sep 12, 2005 3:05 am

As for boost control, dont put your foot into it!!

Or, disconnect the turbo compressor and wastegate hoses from the boost soleniod, and connect them to each other. Wastegate pressure is only 5psi (on a VF-11, our stock turbo). But you will physically have to put them back to regain the higher boost level.

You could spend the money on a dual stage boost controller and have them set accordingly.

Hope that makes sense.

crappyrice · Post by **crappyrice** » Mon Sep 12, 2005 3:08 am

ok so the wastegate opens at 5 psi? i thought that it stays closed until the boost reaches its peak set level 8 psi in our case then it opens up, and then wouldent the air flow decrease casue of less pressure buildup, thus makeing the constant boost less than 8?

i looked into the 2 stage boost controllers but they wont work to decrease the boost, is there any way to just get rid of a wastegate, LOL probably not

stipro · Post by **stipro** » Mon Sep 12, 2005 3:17 am

crappyrice wrote:ok so the wastegate opens at 5 psi? i thought that it stays closed until the boost reaches its peak set level 8 psi in our case then it opens up

Well, yes but it goes to 8psi because the boost soleniod bleeds off the pressure to the wastegate, in other words it takes 8psi on the compressor side to reach 5psi on the wastegate side.

i looked into the 2 stage boost controllers but they wont work to decrease the boost, is there any way to just get rid of a wastegate, LOL probably not

Yes, but that wont help you any. Not to decrease pressure.

91White-T · Post by **91White-T** » Mon Sep 12, 2005 3:46 am

You COULD just disconnect the wastegate actuator arm. Then you get no boost at all.

wrxsubaru · Post by **wrxsubaru** » Mon Sep 26, 2005 7:41 pm

Binford wrote:Actually. the turbo Supra has more like 220 hp, if I remember correctly. The factory weight rating is 3500 lbs, again, if I remember correctly. The 5.9L V8 powered Supra sitting in my driveway weighed in at around 2800 lbs on a truck scale, and is estimated at 475 hp.

First since he said his friends supra was twin turbo that means he has the 1zegte, not the 7mgte that the U.S. only recived. The 1jzegte puts out 276 HP i belive, and is very mod friendley. This engine is very similar to the 2jze in strenght and effinacy so biger turbos and apropiate fuel mods can net some huge relible hp/tq numbers.

sammydafish · Post by **sammydafish** » Mon Sep 26, 2005 8:13 pm

it's louder becasue the turbo is bigger.... put that turbo (single CT-26) on a EJ22 and it's loud too with a BOV vented to atmosphere.

The guy probably doesn;t have a 1JZ-GTE, he probably got confused because most people think all Supras are twin turbo and no one knows they existed before 93 (F&F junkies).

Stock 7M-GTE boost is 6-7 psi BTW. Here's what it looks like on a EJ22 Scoob ... sorry for the crappy pic, it doesn't do the size of this turbo justice, for a stock piece, it's freakin huge. Almost the exact same unit that came on the 3S-GTE in the GT4 and MR2. It's an awesome turbo for small engines (3S-GTE is 2 liters) It's pretty small for something as large as the 7M, but makes for instant spool. I was able to make a little over 300 rwhp with it and pretty much stock parts before I started my twin project.

sammydafish · Post by **sammydafish** » Mon Sep 26, 2005 8:15 pm

found a better one

dzx · Post by **dzx** » Mon Sep 26, 2005 8:30 pm

That is pretty big, at least as far i can tell from comparing it to the dipstick

Project_Legacy · Post by **Project_Legacy** » Mon Sep 26, 2005 8:47 pm

i think its loud cuz the supra has the BOV and his probly jus has the bypass valve.

sammydafish · Post by **sammydafish** » Mon Sep 26, 2005 8:53 pm

Project_Legacy wrote:i think its loud cuz the supra has the BOV and his probly jus has the bypass valve.

Supra is a metered air system too, it has a bypass valve just the same. It could have an atmosphere BOV but then he'd have to deal with stalling and hesitation. A lot of people still seem to do it though, just because they like the sound

crappyrice · Post by **crappyrice** » Mon Sep 26, 2005 11:10 pm

2 more questions. i ewent back, and he was revving his supra on standstill, holding down the clutch i think, and the turbo still spolled up, and when he hit high rpm's the bov would release the air, just like its supposed to when ur driving. but how come when i put my legacy into nutrel and rev it up, the turbo dont spool up at all?

and secondaly can u explain the function of the hood scoop, i know its a functional hood scoop, but is that the reason my turbo didnt spool up on standstill, casue there was no air moving into the hoodscoop to help spool the turbo?

vrg3 · Post by **vrg3** » Mon Sep 26, 2005 11:17 pm

Your turbo is spooling. You just don't hear it.

The hood scoop's purpose is to let hot air escape from around the turbo.

crappyrice · Post by **crappyrice** » Mon Sep 26, 2005 11:58 pm

do i not hear it casue its not producing enough or any boost?

also it makes sense to vent hot air, but when ur actually driving doesent the hood scoop "scoop" up air and put in under the hood somewhere? if so isnt that bad then becasue its not doing its job and all that hot air is gonna stay there???

vrg3 · Post by **vrg3** » Tue Sep 27, 2005 12:02 am

You don't hear it when it's spooling up because Subaru designed the car's plumbing to muffle as much of the noise as possible. This includes having a recirculating blowoff valve, which is why you don't hear the pressure being released either.

Pop the hood of your car and look down in the engine bay. You can see right to the ground. Air coming down through the scoop when you're moving doesn't just get stashed away somewhere under the hood -- it gets blown out under the car.

crappyrice · Post by **crappyrice** » Tue Sep 27, 2005 6:37 pm

but isnt the scoop connecteed to the turbo?, what happens to the hot air from the turbo once the car is movieg, in relation the the scoop?

mhrallyteam · Post by **mhrallyteam** » Wed Sep 28, 2005 12:20 am

Air comes in through the scoop, around the turbo, cooling it down a bit and then exit under the car, where the pressure is lower.

crappyrice · Post by **crappyrice** » Wed Sep 28, 2005 1:53 am

OHHHHHHHHHHH, i thought that the hot air goes up out of the turbi, so now it makes sence, that it forses cool air by the turbo to keep it cool, by forcing the hot air down.

so what about turbo cars without hood scoops? how would they release the hot air?

also on cars that are twin turbo, would u need 2 boost controllers?

Subtle · Post by **Subtle** » Wed Sep 28, 2005 2:12 am

If you still have the "chimney" over the turbo you should
understand that it guides some air from the scoop to the
turbo when at speed. When the car is parked the shape of
the chimney is well suited for venting hot air up through
the scoop.

crappyrice · Post by **crappyrice** » Wed Sep 28, 2005 2:15 am

YES thats what i thought, so the thing istnt really connected to anything though riight, it just opens up on top of the turbo

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our turbo vs 87 supra turbo

our turbo vs 87 supra turbo