1.4 bar boost (1.2 bar restrictor)

Driving the supra this morning and decided to push her. Flew up to 170 tweekers and looked at the boost gauge.

Normally, the boost goes up to 1.2 bar but when in final gear (4 speed auto) which is somewhere after a ton, the boost goes up to 1.4 bar (where is was at 170).

Chris Wilson said i didnt need my Blitz Boost controller and said he would put a 1.2 bar restrictor ring in my first de-cat instead.

So the question is, how can the boost reach 1.4 bar if the restrictor ring will only flow 1.2 bar max?

Dont worry by the way im running hybrids so 1.4 is supposed to be o.k with them.

So you didnt have the boost controller turned on during this run?

So you didnt have the boost controller turned on during this run?

No, Chirs took it out, its currently in my garage waiting to be re-attached!

Hybrids with a restrictor ring? guess they didnt touch the internal wastegates during the rebuild.

This happened to me a couple of times a few months back. The strange thing was, #1 seemed to be underboosting before #2 came online and overboosted.

I figured it was sticky valves or something, but the problem didn't happen again so I stopped worrying.

P.S. I'm running hybrids with 1.2 bar restrictor and no boost controller.

...So the question is, how can the boost reach 1.4 bar if the restrictor ring will only flow 1.2 bar max?...

The restrictor doesn't exactly 'flow' and absolute number, same as a pipe doesn't flow a fixed number of units. It depends on the pressure difference across.

At such high speeds the engine load was higher, so the turbine was pushed harder - so the compressor turned faster - hence more boost.

It's normal.

The restrictor doesn't exactly 'flow' and absolute number, same as a pipe doesn't flow a fixed number of units. It depends on the pressure difference across.

 

At such high speeds the engine load was higher, so the turbine was pushed harder - so the compressor turned faster - hence more boost.

It's normal.

So i guess the restrictor ring is pretty useless when you get to higher speed / power as it will be faced with holding more gas back which, due to the ring being a constant size, it wont be able to do?

Someone should design an adjustable ring.

waits to be shot down in flames:)

So i guess the restrictor ring is pretty useless when you get to higher speed / power as it will be faced with holding more gas back which, due to the ring being a constant size, it wont be able to do?

The ring does what it is meant to do: restrict airflow so that the undersized JSpec wastegate can operate more efficiently.

The ring is not sold as a full-blown boost controller, rather as an addition to a controller.

is there anyway to tap into the ECU signal and move the fuel cut Via a FCD upto say 19-20psi??

It's sized for stock J-Spec turbos, and even these have varying amounts of flow via the stock wastegate due to production tolerances. If you have hybrids you may need a smaller ring to control boost down to 1.2 bar under very high loads for long periods of time. Refitting your electronic controller will do nothing at all, except to allow you to run ven higher boost, they will NOT allow boost to run lower than wategate pressure, or wastegate pressure less a given flow restictor ring, If you reguarly see over 1.2 bar and need less then I can guesstimate a smaller ring size for you.

It's sized for stock J-Spec turbos, and even these have varying amounts of flow via the stock wastegate due to production tolerances. If you have hybrids you may need a smaller ring to control boost down to 1.2 bar under very high loads for long periods of time. Refitting your electronic controller will do nothing at all, except to allow you to run ven higher boost, they will NOT allow boost to run lower than wategate pressure, or wastegate pressure less a given flow restictor ring, If you reguarly see over 1.2 bar and need less then I can guesstimate a smaller ring size for you.

Ive got no problem in running higher boost if its safe to do so on the hybrids at high speeds cos its not often you get to those speeds anyway.

On an irregular basis, would the 1.4 bar be alright on my turbos Chris?

Ta

Matt

my car does something similar. in 2nd mine boosts at 0.9/1bar/ and in 3rd it hits 1.1 bar. I always back off though becoz will hit fuel cut in a few seconds or so. I don't think 1.4bar will be a problem on hybrids/ and surely you don't hit peek boost in 4th alot of the time so don't wory about it

is there anyway to tap into the ECU signal and move the fuel cut Via a FCD upto say 19-20psi??

yes, the Thor FCD can do just that.

Ive got no problem in running higher boost if its safe to do so on the hybrids at high speeds cos its not often you get to those speeds anyway.

 

On an irregular basis, would the 1.4 bar be alright on my turbos Chris?

 

Ta

 

Matt

The hybrids may be safe, but do you have the fuelling set up to cope with 1.4 bar?

Presumably, if you get 1.4 bar of boost, but you're running stock injectors, the injectors will be maxed out and you would be running very lean. I imagine this could do serious harm to the engine over time.

He's on bigger injectors

He's on bigger injectors

Am i?

oohh What else am i on Chris?! lol

Am i?

 

oohh What else am i on Chris?! lol

I meant Wes is

Ive got no problem in running higher boost if its safe to do so on the hybrids at high speeds cos its not often you get to those speeds anyway.

 

On an irregular basis, would the 1.4 bar be alright on my turbos Chris?

 

Ta

 

Matt

Possibly.

Just an interesting side note, i have std injectors and i hit 1.2 -1.25 bar and my EMU log was showing injector duty cycle of no more than 79% with AFRs of 10.2 and occasionally into the 9s and thats with no adjustments, now i run water injection which will lower the AFRs but it is not going to affect injector duty cycle, the 79% is both input and output, somewhat puzzling!

Just an interesting side note, i have std injectors and i hit 1.2 -1.25 bar and my EMU log was showing injector duty cycle of no more than 79% with AFRs of 10.2 and occasionally into the 9s and thats with no adjustments, now i run water injection which will lower the AFRs but it is not going to affect injector duty cycle, the 79% is both input and output, somewhat puzzling!

Give it to me in English Doc!!

Ah yes but are you running a FPR? If so what is your baseline Pressure?

Just an interesting side note, i have std injectors and i hit 1.2 -1.25 bar and my EMU log was showing injector duty cycle of no more than 79% with AFRs of 10.2 and occasionally into the 9s and thats with no adjustments, now i run water injection which will lower the AFRs but it is not going to affect injector duty cycle, the 79% is both input and output, somewhat puzzling!

Ah yes but are you running a FPR? If so what is your baseline Pressure?

Bog std FPR, i wouldn't of bothered making a comparison if i had aftermarket FPR running higher pressures;)

So we're saying then that 1.25 bar is ~80% duty cycle on the 440's. If it can be scaled up in this sort of fasion then, that means the 440's can handle 1.56 bar at 100% duty cycle.

OK?

I'm just wondering now because I have a Jap spec car coming. My UK car just needed de-cat, exhaust, and a bleed valve. Now I have to start pissing around with restrictor rings and worrying about injectors and stuff.

Can't I just replace the wastegate with one from a UK motor?