Reducing Lag - GA70

[Kyosho]

Hey all

Have my Supra running, and have been driving it around for a while, and it's already starting to bug me, the thing has so much damn lag. It's a PITA!
The car is completely stock except for a 3" exhaust (Which I'm actually planning to change to a 2.5" exhaust to lower the power band a touch)

Now, if I boot it off the mark, it's VERY sedate, as in, a lancer can keep up beside me, and if they're quick enough off the mark, get ahead for a touch.
Now, once I hit 4500RPM, it just takes off up the road, and that's the end of that.
But the auto shifts out at what seems like 6500RPM, so I'm only making good power for 2000RPM basically.
Now, on stock turbos, I'm finding this unacceptable.
It starts to boost quite low, but it doesn't seem to make full boost until 4500RPM, when all of a sudden it comes to life.

Now, it's a GA70 Supra, with the 4 speed auto behind it.
I plan to keep this combo, as it's a daily driver, and I also want to drag it a few times (Nothing insanely quick, just a few light mods)
Don't mention a manual, as my R33 is a manual, and I don't really want one as a daily driver anymore.

Now, if I put on a good FMIC, and a boost controller, and tap boost upto around 17PSi (With something like an SAFC to tell the ECU it's not so high)
Will this reduce my lag?

I'm also thinking of putting in something along the lines of a 3500RPM stally, but I'm unsure what this would be like on the road daily.
As it is, it's bugging me how slow it is off the line, and how small of a power band it has.

So, basically, looking to spend around $1000 - $1500 on parts, will buy a second hand FMIC if it's in good nick etc, and I do all of my own work myself.

So, will the new exhaust, boost controller, FMIC, and a 3000 - 3500 stally make this thing less laggy and quicker off the mark?
Oh, and that's about the extent as to which I want to modify it really.

[love ke70]

standard boost?
me thinks there is something amiss, it should be making boost well before then.
i cant remember what mine was exactly when i had standard twins, but it was around 3200 or so, thats running on LPG, 4.3 diff ratio and under a tonne.
RB20 single turbo on a 6boost manifold is very responsive. up a hill in 3rd i can have the full 9 pound im running well before 3000.

[Lagstar]

That does seem like something is amiss. You should have full boost around the 3000rpm mark. A standard 1G in a 1500kg supra is never going to feel fast, but it should at least feel 'spirited'. I reckon something is not right.. Is there any other symptoms?

[Kyosho]

I know my timing is slightly a little low, it's only running 5degrees of timing, other then that, it runs like a dream (Dizzy is out by one tooth) Going to pull it out tomorrow and fix it up.

The boost guage coming up is NOTHING like my R33, hit the peddal and it basically snaps to full boost, this car is like watching the tacho rev up.
It's not quickly coming on boost at all, comes on quite slowly.


Edit: Once above 4500RPM, it is quite "spirited" to drive.
I knew an I6 2L would never be "fast" but I thought it would be better then this.

[Lagstar]

Let us know if adjusting the timing makes a difference. I can't think of anything else the moment. I started thinking one turbo had blown...

[TA-022]

checked for leaks?

I have a 1GGTE in the Celica and it feels like a rocket and breaks traction at 5k rpm at WOT in 2nd and 3rd.

Definately sounds like something is a miss.

[Kyosho]

No leaks
Turbos are fine (Just bought the car and had to replace the two blown ones on there)

TA022, what's done to your 1G-GTE?

[TA-022]

nothing ... bog stock.

victorian dude bought it and it sat for a year.

i swapped the turbos up for a known good pair i had and flushed fluids then ran it.

still running on its cruddy ol plugs (changing this weekend.



but this is also my 1st real turbo car too so i may be naive

[Karma Supra]

Mine is the same, Things don't really get going untill 4k 4.5k I put it down to slightly larger blitz turbos, although the ported and gas flowed head may lose me some bottom end grunt, it seems to be more lag related. I just try and never let the revs get below 3k. Running 3" decat back exhaust, Trust FMIC and hard pipes, HKS bov and an apexi AVC-R boost controller.

I assumed this was about right for the type of engine it is, its never going to be a low down torque monster, and it doesn't give the huge initial kick up the arse that my old 7M did, but it does build up steam over a longer period of time, and it is fast, it just doen't feel as fast due to the more progressive power delivery. I personally don't think the 1Gs power band suits auto at all, where as the 7M-GTE's does.

I feel dirty saying this... but you need to drive it like a honda.

[Kyosho]

Mine is the same, Things don't really get going untill 4k 4.5k I put it down to slightly larger blitz turbos, although the ported and gas flowed head may lose me some bottom end grunt, it seems to be more lag related. I just try and never let the revs get below 3k. Running 3" decat back exhaust, Trust FMIC and hard pipes, HKS bov and an apexi AVC-R boost controller.

I assumed this was about right for the type of engine it is, its never going to be a low down torque monster, and it doesn't give the huge initial kick up the arse that my old 7M did, but it does build up steam over a longer period of time, and it is fast, it just doen't feel as fast due to the more progressive power delivery. I personally don't think the 1Gs power band suits auto at all, where as the 7M-GTE's does.

I feel dirty saying this... but you need to drive it like a honda.

Yeah, I felt a little bit let down with the auto.

Even stalling it up on the brake, builds about 2 PSi of boost, drop the brake, mash pedal to the floor, and it's just damn lazy off the line!
Hrm...
*Goes and fits nitrous kit to spool turbos on the brake*... I wish!

Hrm...
Might have to do some testing with this thing... Try and make it spool up quicker

But what does everyone think of the proposed mods.
Specificaly the stall convertor. I've always been a manual person all of my life, so I don't really know what a high stall is going to be like to drive.
Anyone know able to inform me what it'll be like daily (I give mine a bit off the mark, but do mainly along the freeway once moving. Going through corners I like to give it a bit of stick to get moving. I hate waiting around!)

[JustCallMeOrlando]

Your R33 will have a newer turbo, there is a good 10 years of technology difference between the turbos.

First thing I'd do is fix the timing. Next I'd get a decent 3" exhaust, make it easier for those babies to spool. Then I'd be changing the intercooler for something a little more efficient, no use running higher boost without it being cool. Tighten the AFM 3 notches to offset the increased boost, this should bring your boost cut to around 18psi if it's anything like mine (best done with a dyno for peace of mind). Then I'd be getting myself a good EBC and setting the gate pressure much higher to prevent boost creep. That should provide the best bang for buck, and remove as much limitations as possible.

Your next step if it works out, would be to grab Rod's dump pipes if they turn out to be really beneficial!

[The Real Roadrunner]

a small stall converter will be fine for a daily as it will let the revs come up abit before starting to move the car much and it will be more fun with spirited driving for the same reason . make sure you fit a big trans cooler at the same time to cope with the extra heat as more friction always means more heat .

[mic*]

As said, advance the timing.

So the turbo's are OK? Def no (minimal) shaft play?

Not a wastegate stuck open or partially open?

I do agree that it sounds amiss for stock. The first test i'd prob do is wack a boost gauge in the line off compressor outlet which actuates the wastegate. Do this for each turbo and compare to see if one or the other is letting you down.

[EldarO]

wastegates might be dodgy.

dunno if the GA70 1GGTE has T-VIS, but if its not working properly, it'll cause problems.

Elmo.

[Kyosho]

Mic, I'd thought one of the wastegates might have been stuck open, but so far, I can't go and play with the car... Too wet outside! Also, the turbos were in pretty good nick from the inspection a mate and I gave them before buying, and they went on the car the very next day. Will check waste gates soon.

JCMO: The R33 also has the advantage of a larger engine... So it's not fair to compare them.
As for exhaust side of things: It has a pretty damn "free flowing" exhaust (Basically, cat, and a rear cannon, all 3" from the dump)
I actually want to change it slightly, as the larger pipe size, gives a higher up power band (From what I've seen) but have to go get things checked out first.
I'm trying to find a FMIC, but also one that's fairly "cheap" (Don't want to spend the earth on a daily, just give it some more kick)

Eldaro: TVIS - I have no idea either