Twin Scroll divider melted in GT35 housing...
Nov 16, 2011, 01:49 AM
#1
Twin Scroll divider melted in GT35 housing...
Has anyone seen this before?
I'll put some pics up tomorrow.
The divider in the turbine housing where the gas hits the exhaust wheel has warped and "collapsed" causing one of the scroll to be partially blocked.
Runners #1 and #4 were restricted, and #1 and #4 valve springs cracked the broke (from excessive heat and back pressure i assume).
Yay
Housing is a GT35 AirResearch, sourced from ATP Turbo.
************************************
Here is the answer from ATPTurbo
"Tell your customer we are working on a stronger unit that can endure circuit racing to extended periods of time without fatiquing that way.
There is stronger material available now for turbine housings, but not in the divided (twinscroll) application that the customer is running.
There is an upcoming release of Garrett's twinscroll v-band housing that will use a stronger casting material but that is 1/2 year away.
If he has to be up and running NOW, going to the 1.06 A/R housing will give him some more strength because that unit has more wall thickness, but it's still not a 100% guarantee due to the stresses of circuit racing.
Please pass this along to your customer.
Thank you."
"Looking at the dates below, he's out of the 12 month warranty period unfortunately.
We are working on a stronger housing for the future so that he has something that will hold up forever on circuit racing though."
************************************
To sum it up, current twin scroll exhaust housings are not and were never designed for circuit racing.
beware to anyone using them.
We have had another GT30 Exhaust housing crack through the divider also. This was on a drift car.
I'll put some pics up tomorrow.
The divider in the turbine housing where the gas hits the exhaust wheel has warped and "collapsed" causing one of the scroll to be partially blocked.
Runners #1 and #4 were restricted, and #1 and #4 valve springs cracked the broke (from excessive heat and back pressure i assume).
Yay
Housing is a GT35 AirResearch, sourced from ATP Turbo.
************************************
Here is the answer from ATPTurbo
"Tell your customer we are working on a stronger unit that can endure circuit racing to extended periods of time without fatiquing that way.
There is stronger material available now for turbine housings, but not in the divided (twinscroll) application that the customer is running.
There is an upcoming release of Garrett's twinscroll v-band housing that will use a stronger casting material but that is 1/2 year away.
If he has to be up and running NOW, going to the 1.06 A/R housing will give him some more strength because that unit has more wall thickness, but it's still not a 100% guarantee due to the stresses of circuit racing.
Please pass this along to your customer.
Thank you."
"Looking at the dates below, he's out of the 12 month warranty period unfortunately.
We are working on a stronger housing for the future so that he has something that will hold up forever on circuit racing though."
************************************
To sum it up, current twin scroll exhaust housings are not and were never designed for circuit racing.
beware to anyone using them.
We have had another GT30 Exhaust housing crack through the divider also. This was on a drift car.
Last edited by RSMike; Nov 29, 2011 at 10:37 AM.
Nov 16, 2011, 10:43 AM
#6
We were going to use a FP turbo a while back, but there was like a 6month wait on HTA82's.
So we got a GT3582, and i brought in a Twin scroll housing for it.
Car is a SR20 that does circuit racing, has made 700whp on E85 and 36psi of boost.
BUT it only uses about 500whp for circuit racing, 0.82 Lambda. Revving to 7500rpm.
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Nov 16, 2011, 01:45 PM
#10
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The car must have had some serious EGTs to cause that. Its a fairly stout housing and that should not happen under normal conditions. By the coloration of the housing, you can tell it got very hot.
Nov 16, 2011, 01:55 PM
#12
No anti lag.
All of our E85 equipped cars have that colour in the exhaust pipe, all the way to the tip.
I dont know if it's from additives they put in the fuel (anti corrosion etc).
Lambda was 0.80 to 0.82.
We've seen another ATP housing crack through the divider before on the other drift car with a twin scroll 3076, but not warp the divider like that.
IF the EGT is too high, what lambda should be be tuning to?
The car does 20minute sessions at full noise, and with a turbo beanie.
Cheers, Mike
All of our E85 equipped cars have that colour in the exhaust pipe, all the way to the tip.
I dont know if it's from additives they put in the fuel (anti corrosion etc).
Lambda was 0.80 to 0.82.
We've seen another ATP housing crack through the divider before on the other drift car with a twin scroll 3076, but not warp the divider like that.
IF the EGT is too high, what lambda should be be tuning to?
The car does 20minute sessions at full noise, and with a turbo beanie.
Cheers, Mike
Nov 16, 2011, 04:46 PM
#13
Evolved Member
How much boost is it running at .82lambda? I prefer to stay away from target AFR conversations as people have their own opinions, and it'd help to monitor EGTs when tuning something that aggressive - but fwiw I tuned a naturally aspirated Honda on E85 recently and I ran it richer than that.... but I'm no professional. Fwiw, it made around 260whp so it must have been happy enough with what I did.
For a turbo car, especially running high boost - I'd personally be aiming quite a lot richer than that myself. And in case you are wondering, I realise that .8lambda with E85 is a lot more fuel than .8lambda on petrol, to my understanding thats further compounded by rich best torque and lean best torque also come in at higher equivalence ratios - so E85 = nomnomnom more fuel.
For a turbo car, especially running high boost - I'd personally be aiming quite a lot richer than that myself. And in case you are wondering, I realise that .8lambda with E85 is a lot more fuel than .8lambda on petrol, to my understanding thats further compounded by rich best torque and lean best torque also come in at higher equivalence ratios - so E85 = nomnomnom more fuel.
Last edited by MrLith; Nov 16, 2011 at 04:50 PM.
Nov 16, 2011, 05:21 PM
#14
the redish color is an additive. our e85 in the states doesnt have it. actually no pump fuel has it here. the additive I believe is a known carcinogenic. torquo race fuel additive colors combustion like that.
Last edited by 94AWDcoupe; Nov 16, 2011 at 05:26 PM.