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The mkiv Supra Owners Club

Anyone got a big twin/single manual?


Nick

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Originally posted by Nick

Weka - you have pm :)

 

Is the T67 GTQ a modified Greddy T67 kit?? Would it also be able to handle the abuse of a sustained 2hours of 120mph-180mph (except stops for petrol!!) on the autobahn....? That's something ChrisW pointed out, some of these single/twin kits wouldn't take that sort of treatment but are perfectly reliable for drag racing or a track days...

 

I wasn't meaning the TURBOS will fail, more that most kits seem to have TOTALLY inadequate heat shielding, and whilst OK for quick blasts, sustained WOT running would probably have something under the bonnet on fire. Mazda RX-7 single turbos kits are chronic for this, with melted brake master cylinder reservoirs, molter steering column rubber bist 9cos most kits are US based and they don't have a column on that side over there...). Tread carefully, look at the extent Toyota went to with shielding and packaging the turbos, and see what the various makers offer.Turbos get BLOODY hot.

turboheat.jpg

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Originally posted by Chris Wilson

Turbos get BLOODY hot.

 

I can back this up - seen something heading towards the picture. Friend had a quick 2wd Sierra Cosworth (not sure on power, but would go to over 7kRPM in top). After a good run the turbo would light up under the bonnet - even after stopping and openeing the bonnet up. Quite amazing really!!

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I'm suddenly glad that I went to so much trouble to keep all my heat shielding in place . . . :eek: I've also got an asbestos-type jacket which fits over the turbo exhaust housing. What other solutions are there Chris? Big vent in the bonnet? If so, cold air in, or hot air out?

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It's the radiated heat, rather than convected heat you need to worry about the most, so shielding is essential, and the good heat shield materials do not come cheap. If there is room run 2 or 3 layers of composite heat shielding with at least a 10mm air space between each layer. Done properly you should be able to virtually put your hand on the outer layer without burning yourself, given 3 layers and state of the art materials, even with the turbo cherry red. Finding room and mounting so the vibes don't crack the thermal barriers is the hardest part. Thermal blankets are good, as they keep the heat energy inthe turbine housing where it belongs.

 

A properly ducted air flow to around the turbo area will of course help.

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I think these heat shields with a vented bonnet should keep things cool under the hood.........

 

Boost Logic ABS Heat Shield--

This heat shield protects the ABS unit and brake lines from the heat given off by a single turbo kit. The heat shield extends from the top of the ABS unit to the top of the frame rail. Many "tuner" turbo kits come with a heat shield to protect this area but are very ugly and bland. The plate and brackets are made out of polished 304 Stainless Steel and will not warp. This heat shield adds another polished touch to the engine bay while being useful.

 

Boost Logic

T4 Exhaust Housing Blanket---

This heat blanket works so well in keeping under hood temperature down that you can even rest your hand on it without being burned. These sell like hotcakes and are VERY hard to get so get your order in now!!

 

Boost Logic Inconel Heat Shield---

This heat shield is a perfect upgrade to keep engine temps down. Use it in conjunction with the Boost Logic Turbo Blanket for the ultimate in heat reduction!!

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The first time I saw a turbo glowing like the pic posted by Chris, on a Cossie, I was amazed, this was after the car was stopped and the bonnet flipped, it took a while to cool down, a real advert for turbo timers though. Then I wondered how long other bits would survive given the intense radiant heat, it was like standing by a fire. Remarkable engineering to be able work at such incredible heat ranges.:respekt:

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I used to have a Escort RST and had no idea how hot the turbo got until I flipped the bonnet one night after a 50mile WOT run home and saw it sat there glowing red...

 

I suspect proper heat shielding isn't supplied with the turbo kits because it doesn't look flash and polish up well. I have to admit it's not something I'd thought about, only considered the air intake... Doubt the heat will do an unprotected fibreglass bonnet any favours....!

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I've got one of the boostlogic exhaust housing jackets, not quite as pretty as the one Ian posted but same sort of idea. It seems to work pretty well, but I haven't done much high boost running yet. I would imagine that the best way of reducing this problem is keeping EGT's down around the 700C mark, which is something I'm hoping to achieve.

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Originally posted by Wez

OK cool, does anyone know what a safe maximum is for the runners on a supra, 900 - 950?

 

:stupid:

 

Too cool, in fact, heat energy is good, short of too much heat energy, the consnesus of opinion is below 850 degrees is perhaps too LOW for max turbo efficiency, so 700 or below may be losing turbo efficiency.

 

As for a safe temp for a stock car, I'd say below 875 / 900 should be fairly safe, in the port region. Above 900 is risky, over 1000 is VERY dodgy.

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Originally posted by Wez

OK thanks chris, I could bring the temp down a little by adding a bit more fuel at the expense of power.

 

:thumbs:

 

Madness, totally counter productive, fix the REAL cause of the high EGT's (Probably a combination of too small a turbo size being run too fast and trying to run our excuse for good octane fuel). Add octane and bigger turbos, and map the timing and fuelling to suit, and the differences should be staggering. The MAIN bugbear with turbo engines with real go in the UK is fuelling their octane needs.

 

MonkeyMark was here today, he was on about drag racing, and he turned my thoughts, unintentionally, to other engines. A 10 litre ali big block Chevy would run OK on 98 octane, although not as well as 100 plus, but would liven a MKIV up a bit :p

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