Im considering jet hot or the other coatings on the manifold of my m2 ball bearing twins (stock manifold). If I were to get it coated...would that cause considerably less cracking over time?

thanks for the input.

have any of you had any issues with doing this modification?


thanks


j

 

artguy, try contacting carlos@the-rotary.net

He's on the Forum under that name. I recall that he has tried a number of high-temp coatings on the turbos and even inside the engine. You may be able to find his old posts on Steve Ciriani's site.

http://www.scuderiaciriani.com/rx7/index.html

 

thank you...i will look into it more...ive not found a great answer as of yet

j

 

Let us do know, when you find anything out. When I go BNR's, and I plan on having my exuast manifolds and stuff done. CJ

 

yes it should eliminate the cracking

 

anyone else try this??



j

 

ArtGuy. Sorry about not responding to you PM, but my email is wacky in that it's not letting me send out any emails since yesterday. Anyone know the solution to continuously getting "Relaying not allowed" error messages?

Now on to more topical discussions:

Coating: Tried a half dozen.
- Love Airborn Coatings for non-exhaust/cosmetic applications like my intake track. Great service, excellent finish and by far the best value. They have three facilities but I've only used the NC one.
- HPC Extreme and JetHot 2000 are the only ones that I've tried that hold up to the inferno that is our EGTs. Even these have very limited durability on the inside of the exhaust manifold or turbine manifold. Swain's White Lightnining DRIPPED from the exterior of the exhaust manifold after about 3K miles. Looked like little stalagtites/stalagmites in the bottom of the manifold. All of these work great on the downpipes and further downstream, due to the reduced temps. But don't try "regular" ceramic coatings as they're likely to fail/crack/flake.
- Techline's DIY BlackSatin has held up on nicely on the exhaust manifold, is simple to applly and even cures while on the car. Very responsive tech support. A nice DIY option, though I can't vouch for it's internal uses.

Maybe it's just a carryover from my obsession with my Iannetti seals, but can you tell that I'm a HUGE ceramics advocate !?!

Cracking in the stock turbine manifold: FORGETABOUT IT!! The best that I've found is to port match the tubine exh inlet opening to the gasket and then slightly radius the entry edge. I believe ( note the lack of factual data ) that the major contributor to cracking on the turbo's exhaust inlet is the extreme localized heat the leading edges experience. Even this will only postpone/slow the rate of cracking marginally. Unfortunately I don't think that any (readily available) coating can sufficiently stand up to the thermal stresses and thereby protecting the edges of the housing. These turbos that I have on now have lasted THE LONGEST that I've seen before cracking and they've already developed the first 2mm hairline after only 5k miles. I've seen BRAND NEW housings develop cracks after only TWO thousand mile.

So how's about those modified stock compressor turbos!!!

Flyin, Racin, and Buildin Rotary Beasts,
Carlos A. Iglesias
'93 RX-7 R-1 (Buildin')
'93 RX-7 R-1 (Sellin')
'95 M3 Sport (Drivin')
'01 Pathfinder SE (Towin')
http://www.the-rotary.net

 

i have a jet hot2k coated DP and UIM [also powder coated] and the place that does it is here in mississippi. i have seen coated housings for turbos before, and from what i know, it lasts, and does prevent premature cracking and heat stress....

pm me if you need more info, i can get it for you...

louis

 

Ceramic coatings will not prevent the cracking due to the irregular geometry and over constraint of the stock turbine housing and manifold setup (especially in sequential config). Reducing hot spot temps should help and Carlos's suggestions for port matching as well as applying ceramics can do that. But when those puppies start to heat up the castings do not have a chance to grow without constraint ... stress and cracks are a natural result.

 

carlos..i sure do appreciate all the good info and the time you took to make that post. thank you very much.

I am happy with my garrett gt30 internal upgrades so far...I put on about four thousand miles with no signs of cracking at all. they run a lot cooler than the stock set and my motor is streetported so I dont know if that has contributed to the longevity without signs of cracking or not. I also cool it down every single time i drive it.

I ask..not out of fear of future cracking on the stock set...but because i have considered porting the exhaust manifold some to allow for higher flow...and to help clear up the the bottleneck that the stock manifold is. have any of you attempted this modification?

I know the stock manifold cracks early...I am sure one that is ported will crack even sooner. Have any of you tried doing this at all?

thanks to everyone else for replying as well. It sounds as if doing this all is a waste of time really. Its not a daily driver so I dont look to it for 100000 mile reliability...but while I am doing other work on the car this idea came up.

so..i guess the question is...have any of you ported the stock manifold out at all?


j

 

The reason that you got the error message "Relaying not allowed" was because the SMTP out bound mail server did not reconize your IP address as comming from its local network.

Example if you have a MSN e-mail account and go over to a friends house and jump on his network, and his internet service provider is AT&T, you would not be able to send e-mail via AT&T mail server. You would have to reconfigure you e-mail client and point it to AT&T's out going e-mail server, which is called a SMTP server, and then you would be able to send mail. The reason that a SMTP server will reject e-mail not comming from its network is simple... its to cut down on SPAM.

 

carlos@the-rotary.net -
You are right about Thermal coatings. I haven't found any manufacture that makes a coating, "available to the public," which can handle the heat.
To help stop stress cracks before they start, port match and radius all corners, remove and contour any sharp edges. This will help to increase the manifolds life span but the turbo manifold will eventually crack. The manifold's design just can't handle the heat.

 

thanks guys...tis appreciated


j

PS..have any of you had any luck with porting the manifolds at all?