BenR

iTrader: (2)

Corrected.

ZX-Tex

iTrader: (15)

^^ FWIW I am using water injection as well, 5 GPH nozzle, and my exh-mani to turbine inlet studs (T2) were very tight after the track day at MSR. Regular BEGI-supplied studs and clinched (self-locking) nuts.

JasonC SBB

MSR is a high speed high hp track?

Savington

iTrader: (31)

No, I didn't say that. I have had hardware failure at every single track in California, except for Infineon which I have never driven.

Miatamaniac92

Don't you think **** would start breaking before EGT got high enough to start effecting the hardware?

For example, RX7's run a whole lot higher EGT. What do they do for the solution?

What's the highest EGT people are seeing without engine damage?


My experience (I'm slow, I don't break SM records) this year; new hardware and plained the manifold after a stud sheared. 3 trackdays, no loosening.

Nordlocks melt and are crap for the heat we see.

Right now I have a combination of Audi copper coated nuts and Catepillar-supplied nuts. I'll see if there's a significant difference in the long-term.

For a data point, anyone running a turbo blanket having this problem (if so, I bet it's worse)?

Chris

ZX-Tex

iTrader: (15)

No, more of a medium speed, but with decently long acceleration runs in two or three spots. At the end of the faster straight I was hitting about 100 mph, FI race tire Miatas were probably hitting 120 (carried more speed onto the straight, deeper braking).

The fast track day course here is Texas World Speedway. I have done 160-170 mph on the front straight on a liter bike. It is a looooong straight, with a very fast corner at the end of it. I have not run my Miata there... yet...

hustler

iTrader: (6)

no but I was able to break 130mph in 2 places. lol

hustler

iTrader: (6)

my pincher nuts can be spun on and off now.

hustler

iTrader: (6)

I'd love to hop in someone's car who doesn't have this issue and see if I can make it happen.

Chris, is your exhaust hard-mounted?

curly

iTrader: (25)

Just putting this out there, but I wonder if it has anything to do with how much curbing we take and how stiff our suspension is. Granted all that, especially the curbing part, has to do again with how fast we are.

Miatamaniac92

It's mounted to the turbo then flexpipe followed by the cat and hangers for the rest of the exhaust.

Chris

Savington

iTrader: (31)

I don't touch curbs at WSIR, still have the same problem. I pound 4-5 curbs a lap at Buttonwillow, same problem. I sip Cris at Autoclub, same problem. I **** twins at Thunderhill, same problem.

JasonC SBB

I also think tuning will have a bigger effect on EGT than the driver.

Think about it. The difference between a fast driver and one who's 3 seconds behind could simply be higher corner entry speeds. In a 2 minute lap the slower guy may be a total of 2 seconds longer on the brakes and 5 seconds shorter at WOT. Sure the faster guy may be spending 1 sec longer on the gas on the 15 sec main straight, leading to higher peak temps in the studs ... however 2* less timing at the topend can mean 100*F higher EGTs which would heat up the studs more than the extra 1 sec on the gas.

Laur3ns

I talked to the machinist of OTS about, that my business puts a little money in for fun. They do European Auto Cross with a FIA certified 1300kg and around 500hp monster build from scratch:


They run a GT35R on a 2l Ford Duratec engine at 30psi. The turbo hangs down on a SS tubular manifold. He said to use stainless studs, not hardened steel. The properties of steel are just not right: the expansion is different than the manifold material, plus is glows earlier and becomes soft. Although they take the engine apart after every weekend, they have no loosening in between practice and race sessions so there is plenty of heat cycling.

They run v-bands for the downpipe connection and are going that route for the turbo to manifold connection as well, just because it is so much easier.

If I don't fix this issue, I am going to get a TIAL housing and have him make me a tubular and modifies downpipe and some v-bands. The manifold would not be cheap 1-off, but alot cheaper if more are interested.

Laur3ns

Elaborate please...

ZX-Tex

iTrader: (15)

Does the turbo use a stainless or a cast iron turbine housing? If it is stainless, then yeah for sure matching the CTE could help with stretching.

Laur3ns

Looked cast. Standard housing. They will switch to a TiAL v-band housing at some stage. And a turbine rpm sensor, how cool is that?

Their manifold is stainless so fabricating the studs from that same material helps. I have a cast BEGI-S and a cast housing, but I dont think cast studs exist/will work?!

Laur3ns

It starts failing earlier than that. I had someone shave 10s off my time while I was learning and Ive had **** fail before that. My dad however, cant get temps above street level.

Laur3ns

Had a track day last Thurday. Lots of driving, off which one hour was non-stop save for some slow laps because I still need to get my cooling together.

So, yesterday I unloaded the car and checked the studs. The single one stud that came loose last time I put together and applied Resbond to the stud before putting it back in the manifold is still tight. I cannot spin the washer. I can on most other studs - haven't checked all: heatshield is still on.

The one that is tight is the front top stud - the one that actually carries alot of weight and was loose every single other time. So I am sort of thinking this Resbond will help in a way.

So, I am going to do next week:
1) Resurface the flanges of the turbo and manifold (both sides)
2) Put new machined stainless M10x1.5 studs in manifold with Resbond
3) Use whatever nuts the guys from OTS use, with Resbond
4) Meanwhile new exhaust gasket and exhaust nuts are going on.

And run at Spa Francorchamps the week after.

hustler

iTrader: (6)

spooky...did you have a failure or not?