Interesting to see and not real surprising. These twin scroll housings I believe were designed for Diesel applications with a maximum EGT around 850C. That's why I'm interested in the new Garrett twin scroll housings that prototypes where shown at SEMA. I would assume they are actually being built for gasoline applications.

The Garrett GT housing I believe is designed for 900C-950C EGTs. The Mitsubishi TME is built for even higher EGTs then the normal Ni-Resist Mitsubishi housing due to the anti-lag system. Above about 800C, material choice can really make a difference in steel/nickel-alloy components.

 

+1, what E85 are you running? Pre-mixed drum fuel?

 

Wow that is wild looking. You said the resulting back pressure broke some valve springs as well?

 

Wow. HOT. If that car were mine, I would run a digital EGT gauge with high temp recall feature. If you are on a budget, you can strap one of the higher end FLUKE multimeters to the AC vents on your dash using zip ties for use during the race and then remove it after the event. They feature a large, backlit digital display screen, and will record the highest temp reached.

There is no good reason to not monitor EGT's on a turbocharged race car. A digital EGT gauge has a far more precise readout than an analog gauge.

Alternately, take a look at the SPA Design, dual, digital EGT gauge. Granted, it is a relatively expensive instrument(about $500U.S.). But, it is an extremely accurate, microprocessor controlled dual circuit gauge You can monitor two combustion chambers, via twin thermocouples, simultaneously. It features dual, microprocessor controlled, built-in warning lights. Each light is user programmable for any given temp....all in one compact EGT gauge. The SPA also plays back the highest temp reached. It is a 2&1/16" gauge. It displays in either Celsius or Fahrenheit. This is the way to go IMO.

 

Fuel is Gull Force pro (E85), direct from the supplier. 200litre drums.
Please dont assume that fuel has caused this.

We will be installing EGT sensors, hopefully one per runner.

What is the best way to solve high EGT's?

More fuel?

 

Take a look at the newest SPA Design EGT gauge, since they are dual gauges, you would be able to monitor all four holes with just two dedicated gauges, providing one user-adjustable visual telltale warning alarm per cylinder and four separate digital readouts on just two side by side gauges.

 

You know the possible causes for high EGT's on turbocharged gasoline engines better than most of us do Mikester.I'd say that you are right in that fuel quality is not an issue.

Too lean as you yourself suggest above is one of the usual suspects. So, you have to recheck fuel volume and delivery as well as the fuel mapping. IC heat transfer efficiency and core heatsoak. Too high a static compression ratio resulting in too high a dynamic compression ratio under boost. Excessive exhaust back pressure contaminating the combustion process. Excessively high boost levels for the octane of the fuel. Sparkplug heat ranges. Too tight of an exhaust housing or restrictive of a post turbo exhaust system. Too high ambient air temps. Insufficient radiator heat exchange efficiency. Too high coolant temps etc.

I would suspect a fuel delivery problem. Is there a fuel pressure gauge on the car to monitor fuel delivery at WOT under full load ? Falling fuel pressure at high boost/high engine RPM's is an indicator of fuel pump problems. I imagine that E85 has a much different tuning requirement than does gasoline. I know that it requires a much higher volume of fuel.

 

if you believe egt was acceptable, send a piece of the housing out for composition measurement and compare to published steel compositions. might find out that its not that great of an alloy.

 

i saw this on a customers car with a stock turbo.. high boost on a stock map -_- egt through the roof

 

Send it my way, we have an XRF gun I can test the material with and tell you the composition.

I would bet it is not meant to go over about 850C though. Gasoline motors go well over that, which is why Mitsubishi uses the Ni-resist material and not lower grade cast iron. Same reason they went to the higher grade nickel alloy in the TME housing to deal with the anti-lag.

A housing designed for a maximum operational temp of 850C means the engine usually should never go over probably 750C. If a diesel is going over 750C, you have problems. A gasoline motor cruises down the freeway hotter then that. WOT for extended period means 900C is very likely on a gas motor. I would imagine E85 is still going to reach 850C with a consevative tune. The turbo manufacturers are currently advertising turbochargers that can handle 1000C for future lean burn applications.

"Wrong tool for the job."
These twin scroll housings currently being used weren't designed for gasoline applications.

 

thanks everyone for the info.

i'm just thinking "yeah but why us?"
aren't other people around the USA using and hammering these products just as hard as we are?

We'll have to see how the BW EFR stainless steel housing will hold up that we have sitting on the coffee break table Makes a very good paperweight! lol (it's Very heavy)

 

I've heard of this happening on the EVO housings.

Actually, wasn't this the same failure that happened on an HTA71 with the Ebay 11.5 housing?

 

Has the car always run on this fuel Mike? Was it tuned on this fuel or another?

 

if you are pushing this SR20 to the limit for 20min sessions - my suggestion would be to integrate bungs for EMAP and EGT at the same time. i believe you may find the EMAP exceeds a 1:1 ratio by a large margin - this has a huge effect on egt getting high. keep EMAP lower then Intake manifold pressure (aka positive dP) and you are in business - the compressor wheel is literally turning the crank over.

at the end of it all - the EFR8374 1.05 will probably be the call for this nissan

i agree, this alloy is likely cast grey iron... just not up to supporting this level of temp. D5S, ni-resist or stainless steel would unlikely end up in this condition as they are rated to much higher temp operation than grey iron

you are correct - i suspect they were running this housing beyond the material's thermal capability. Sometimes housings live no problem from this, others will fail like RSMike found out. coating the housings does seem to help them live much longer fwiw, i believe becuase it cuts down on surface stresses


i had the pleasure to meet the Manager of Mitsubishi's Turbocharger Division recently. very interesting guy, and shared some cool insights about their turbos. they were really impressed with the efr's

i dont know anyone in the US who pushes an sr20 to 700whp for 20mins at a time. either drag cars, drift cars, or time attack/track builds. none of them see the thermal loads that your car sees. get some EGT and EBP data for this turbo and then install the efr on the car!

 

Hard to say, I don't know many people using that exact housing - as people have eluded to maybe ATP used a material which is probably pushing its luck to handle race conditions on a gasoline engine, that can't be counted out.

As someone else mentioned, you'll know many of the things which can cause high EGTs so I'll not bother trying to add anything there - though for what its worth, tuning (or other issues such as fuel delivery resulting in a "tune" issue) can have an amazing effect bits bolted to the engine itself, even if those bits should/can normally handle normal operating conditions fine. I've seen a factory turbo Skyline cast exhaust manifold damaged from running too little timing, for example - though you could otherwise never call the stock exhaust manifolds on those things made of material or design not suited to gasoline.

E85 is a tricky thing, it has such epic knock resistance that you potentially can do things with it that you'd not be able to on petrol as with straight BP98 the engine may start knocking its head off while E85 may just stop gaining power, but there could be other hidden "delights" going on.

When you get set up to monitor EGTs, it'd be interesting to record peak EGT with the current AFRs, then throw 10% more fuel at it and try again.

Realistically, it could well be a fatal combination of:

- Possibly tuned a bit too lean
- Material of the turbine housing not suited to the purpose
- The turbo is being pushed to or past its limit, which isn't normally an issue as most people using GT35Rs making this kind of power normally only do it for drag racing or at worst time attack... a 20minute race session pushing a GT35R past its power rating is pretty epic.

There's probably a reason turbos like TR30Rs etc exist, as they're designed more for this kind of pummelling.