trialattorney

I installed Carl's kit on my 16 valve and I think, now that the bugs are out of the system, it's great. However, if I were working with a 32 valve, I would neither supercharge nor turbocharge - I would bore it to a 6.4 or 6.54 liter. Visually, the motor looks stock (so if you live where you have to smog the car, no problems) ; second, the engine was engineered for this size motor so no problems: third - it will much more reliable and the cost differential, while greater to bore than to super/turbo charge at the beginning, in the long run, I think it's the only way to go. Or, you could do as English Marcus did - bore to 6.4 then supercharge - the car is incredibly fast and powerful. We're all trying to get Marcus to dyno it. Anyway, to sum up, supercharge your 16 valve, bore your 32 valve. One last issue: by doing any of the above, you are materially affecting the value of your car forever, so be sure that, in the long run, that is what you want to do. I run my supercharged 16v at the track 2 - 3 times a month - I think that speaks well for Carl's kit (with a much larger pop-off valve). Plan on spending a minumum of $10k, not including brake and suspension upgrades. Once you start down the sllippery slope, there will lots of expensive things to add on - like racing seats; harnesses, fire suppression; roll bar or care; oil sump kit; etc......just have fun whatever you decide.

largecar379

Mmmmm......

for OB's:

how about stroke a 5.0L, then build it with Euro 16V top side stuff, and then add a blower...!!!!!

that's where I'm headed-

--Russ

adrian928se

Les "trial attorney", what make/type of "much larger pop-off valve" have you fitted?
Thanks

backnblack

Just thought I would post this page, since this topic came up here.

http://www.stealth316.com/2-turbotemp.htm

Doc Campbell

Questions and thoughts...

I have a (sort of) stock-engined dearly loved '89 928 GT. I would love more grunt. For me the debate is between modest boost supercharger (e.g. Murf stage 1) and a stroker engine ($$$$). Problem: despite all sorts of fiddling, I still have heating problems on hot summer days in traffic. Yes, the fans work, the flaps open, the core is clean, there is no trash between the AC grid and the radiator.

Boost will compound the problem. Air:air intercooling won't help at low road speed (read: heat soak); air:water theoretically would be better, but more complicated than air:air. So, is my choice SC with air:water vs. stroker and totally depleted bank account? Has anyone tried extra capacity radiators (like the Devek unit that used to be around) for extra cooling on the street?

I have a heavily tweaked 2001 Audi S4 (V6 Biturbo). With stock engine, stock air:air intercoolers are fine. Unlike sharks, chipping this engine (which I have) brings major joy. I can't push things more without doing something to cool the intake charge. Fitting bigger intercoolers requires cutting chunks out of the body (if you think the 928 engine bay is tight....), so folks have looked for other alternatives. I've seen data on spraying CO2 on the IC's, and you can get major (below ambient) charge temp reduction; the obvious problem is that you need tanks and refills. The biggest problem is that, set up right (read: actually do some good). The CO2 is gone in minutes. Good for drag racing, but not much else.

However, some Rube Goldberg folks have done stupid simple stuff like set up water mist systems (like windshield washer motors, reservoirs, mist sprinkler heads (I know, I know, not German engineering)) to spray the outside of air:air intercoolers with some good effect. There are commercial kits available to do this too. They don't cost much. Does anyone know if this has been attempted on sharks? Maybe with the right sensor, you could turn the mist on at low roadspeeds (or high charge temp)..........

RyanPerrella

Welcome

We can never have enough Doc's and Dr.'s

As for CO2 and water mist systems, some people here may know about that, but I would try teh 944 forum for those general questions or a honda forum, thye are all into that stuff.

As it stands now there is no kit for a 928 that does those things, it would all be made by you, so there is no reason not to look for some help on that elsewhere. Let us know what you come up with.

As for Radiators, 928INTL makes them now and from what ive heard the Devek ones were crap for a number of reasons. The ones currently available should last a much longer time.

If you go with a Murf Kit I think he has an updated fan design as well so thats something to consider if you go with one of his well put together kits.

Good luck

PS: oh and a stroker isnt just $,$$$ its $$,$$$, or 2 to 3x the cost of a bolt on Murf kit depending on how deep your pockets are.

hacker-pschorr

A stock GT should not overheat even in death valley. Until you resolve this issue, doing anything to increase power is a very bad idea.

You say the core is clean, have you pulled the side tanks off? I have yet to see a 928 radiator that was clean under the side tanks. It doesn't take much to block off a few channels in the radiator which will hurt its cooling capacity.

There are other issues that could also be causing your temperature problem.
Truer words have never been spoken

This site is a great resource to help you out with your issue. There are many threads on this same problem full of great advice. If you need assistance with the search feature, don't be afraid to ask.
It would be better to do so in a different thread since a cooling issue will probably get lost in this thread.

Welcome to the shark tank!!

Tony

and to add...
the simplest thing is the stock temp gauge not working correctly. I was running my car pretty hard under boost one day here in the heat of summer and the traffic...AC on..., the "needle" was sitting fat dumb and happy just above the middle point. I was actually pretty impressed and happy about that! A few minutes later the amber band of the temp gauge lit up....the needle hadnt moved.

While it does work, dont trust the stock gauge alone, and IMHO, when you bump the HP, it wouldnt be a bad idea to install an after market temp sensor on the cross over manifold. I have about 3 of these spare and may start making some on an exchange basis. I tap the crossover and install a temp sensor for use with an autometer gauge. Simple to do...and worth the reassurance of knowing the temp you are REALLY at. Same is true for oil temp and tranny temp.
Perhaps overkill, but i like knowing that stuff.

Either way you will be happy with boost. Litterally transforms the car!

cfc928gt

Doc, I suggest you replace the oil thermostat that sits right about the oil pressure sender. It wears out and prevents proper flow of the oil to the oil cooler. I had heating problems with my '89 GT along with it showing no oil pressure on hot startups. A new oil thermostat took care of both problems.