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The mkiv Supra Owners Club

Turbo lag, is it such a big deal?


JamieP

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I suppose i have to consider those with 2mm HKS head gaskets, lowered compression, and very flat response off boost, that would make driving hard work, but my off boost performance is very good due to stock C/R, not going too mad with the cams, lighter pistons/rods, very light alloys and a nice mapping job have all contributed to decent sub 4K performance.

I changed from 1.00 a/r to 0.81, it helped the lower down spool etc, but not by mass amounts.

So......if building a new motor, stock c/r and mild cams have to be the way forward.

I would HATE a supra with lowered compression, anyway who needs it here? I have 664bhp with no water inj or low C/R and no det on BP ultimate running 11.8 AFR on boost.

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Have I missed something here, the bigger the turbo the more boost it needs to be efficient, no point in running my 76 anything under 1.8 bar:taped:

 

Sorry Dude - I was trying to make the point that if the limiting factor is the octane of pump fuel, then why run a big turbo if you can only use lower boost with decent timing (when it needs higher boost for efficiency), and therefore make no power/torque, or higher boost but no timing (because of detonation risks) and be inefficient with setup.

 

I don't think that anything bigger than a 71 mm (if that!) will be able full timing on proper boost levels on pump fuel. However, I will be testing this theory later this year when I get my 4294 retuned with the new goodies.

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Sorry Dude - I was trying to make the point that if the limiting factor is the octane of pump fuel, then why run a big turbo if you can only use lower boost with decent timing (when it needs higher boost for efficiency), and therefore make no power/torque, or higher boost but no timing (because of detonation risks) and be inefficient with setup.

 

I don't think that anything bigger than a 71 mm (if that!) will be able full timing on proper boost levels on pump fuel. However, I will be testing this theory later this year when I get my 4294 retuned with the new goodies.

 

That makes more sense, but I have no problem running 1.8 bar and good timing on my 76, with a drop of toluene it can go balistic.

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I remember a while back talking to people about the possibility of running a SC with a turbo. In effect using the SC as the first thrust and somehow using that to get the turbo spooling up behind it.

 

They (cant remember who) seemed to think that the project was a non starter due to development costs etc.

 

Single turbo and supercharger.

 

http://www.youtube.com/watch?v=kxdPNvMuPsE

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  • 5 months later...

Bringing back an old thread, now im on the air cooled DBB billet 76mm i still want more power.

 

Having a play on my private track the weekend i am making .5bar at 3200rpm in 6th gear and hits full 2 bar boost at 3700rpm.

 

Still have great spool time, even in first gear i can make 2bar and with my 8200rpm rev limit i have a huge power band and im willing to lose some of that for more power.

 

Turbo suggestions?:)

Edited by JamieP (see edit history)
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You thought about one of the billet Garrett's? I've looked a few times at the GTX4508R and really does look nice.

 

That does look good, worth considering for sure.

 

Top of my list at the moment is the Garrett billet GT47-80, there is a white supra in the states running one on a 3.0L (i will be 3.4 soon) and it goes like stink, beating big bikes from a roll in 1st gear.

 

Will link some videos of it later, im on my phone at the min.

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Bringing back an old thread, now im on the air cooled DBB billet 76mm i still want more power.

 

Having a play on my private track the weekend i am making .5bar at 3200rpm in 6th gear and hits full 2 bar boost at 3700rpm.

 

Still have great spool time, even in first gear i can make 2bar and with my 8200rpm rev limit i have a huge power band and im willing to lose some of that for more power.

 

Turbo suggestions?:)

 

Jamie, you'll never satisfy that power hunger, build a jet car ;)

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That does look good, worth considering for sure.

 

Top of my list at the moment is the Garrett billet GT47-80, there is a white supra in the states running one on a 3.0L (i will be 3.4 soon) and it goes like stink, beating big bikes from a roll in 1st gear.

 

Will link some videos of it later, im on my phone at the min.

 

I think I know the one you mean - is that GT47 turbo still available on a T4 footprint, or will you have to go T6?

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I think I know the one you mean - is that GT47 turbo still available on a T4 footprint, or will you have to go T6?

 

Yeah GT47 is T6, that would be one bonus of going with the GTX45 is that its still T4, just dont want to buy it and change again because its to small.

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