What boost do you run?

[TTM]

10°C to 38°C is a pretty steep increase IMO... Got a map for your compressor?

 

[barks944]

No I dont, it came from GPF who got it from SFR in the US I think. I'm pretty sure it was working pretty hard though . The lowest temperature I recorded in that 20 mins of laps was 23C during the cooldown lap. I don't think the air entering the air filter was even close to 10C, maybe the day was warmer than I recall or perhaps just to the amount of heat under the engine meant the air filter was sucking warm air.

 

[TTM]

When cruising on the road with alternating low loads and throttle lift offs I see pretty much the same inlet temps as ambiant temps. That is with a thick wall intercooler ahead of the radiator. It doesn't take much time for inlet temp to get back down near ambiant temp after several heavy loads.

What your recordings tend to show is that the std IC being a thick brick with no outlet, it takes quite a bit of time for it to cool down to ambiant temp after a few full load runs.

 

[924nutter]

I run absolutely bog standard booost which appears to be 1bar up to about 5,800 then it reduces to about 0.9 on the gauge. Perfectly satisfied with that as it can put manners on a Nissan 350z ( no mate that turbo badge was not just a stick on accessory!) When i want real grunt I get my 996t out. I found a youTube vid somewhere with a guy in a 944 running about 1.4 bar boost keeping a very squirrelly GT2 more than honest so I would say 1.5 bar is plenty if you are running that.

 

[Lowtimer]

Possibly your gauge is a bit out then (which wouldn't be a surprise if it's just the factory gauge built into the rev counter), as those numbers are significantly more than bog-standard boost.

 

[George Elliott]

there is a lot happening under the bonnet on a turbo engine, for sure a big I/C is beneficial, knock detection will allow optimum engine management,

but is it my imagination, or are these cars too hot under the bonnet?

Porsche vented the engine bay of the 924 Carrera GT and 968 turbo - both were high performance turbo applications.

Many of our cars have equal or greater performance than these, yet no engine bay cooling.

This results in Higher Oil temperatures, water temperatures, heat damaged wiring looms, fuel flexi hoses, manifolds....?

I like the I/C air in front grille, and out at the bonnet lead edge. Then a small vent at the rear to release slow speed heat accumulation off the manifold / crossover / turbo / downpipes.

George
944t

 

[T3rra]

Do u think ceramic coated mainfold/ turbo would help? Going poilshed now, but was told the mainfold I got was heat treated via ceramic coat. Which wasn't the case.

 

[924nutter]

ORIGINAL: Lowtimer

Possibly your gauge is a bit out then (which wouldn't be a surprise if it's just the factory gauge built into the rev counter), as those numbers are significantly more than bog-standard boost.

It is the factory gauge in the rev-counter, and it actually goes off the end of the scale at +2 atmospheres so I was rounding it down. I forgot to mention it has a stainless steel exhaust system including the catalytic converter, and stupid 5"x 3" outlet on said exhaust. All gauges are a guide and before I sell it I might just put on the dual vac/boost gauge that I bought for the 924 to make a comparison. Bear in mind that this particular car has only done 45,000 miles and in the six years I have owned it the max boost reading has not changed. Maybe it has been chipped and i don't know it, I've never had it on a rolling road.

 

[924nutter]

I've just looked it up and the max boost is 0.82 bar or 1.82 on the gauge, so I can live with that. I am also happy that as standard the boost is expectd to tail off by 0.3 bar at the top of the rev range.

 

[944Turbo]

ORIGINAL: 924nutter

I've just looked it up and the max boost is 0.82 bar or 1.82 on the gauge, so I can live with that. I am also happy that as standard the boost is expectd to tail off by 0.3 bar at the top of the rev range.

I reckon if the guage is going off the scale it has been modded, I suspect a small brass bleed valve in the boost line that runs down to the wastegate (from the cycling valve under the rear of the intake manifold) and chips.
Tony

 

[TTM]

ORIGINAL: George Elliott


but is it my imagination, or are these cars too hot under the bonnet?

Porsche vented the engine bay of the 924 Carrera GT and 968 turbo - both were high performance turbo applications.

Many of our cars have equal or greater performance than these, yet no engine bay cooling.

This results in Higher Oil temperatures, water temperatures, heat damaged wiring looms, fuel flexi hoses, manifolds....?

I don't think there is any real engine bay venting for these two cars, as the scoop on the CGT feeds the intercooler that's above the engine, and the left inlet on the 968T hood cools down the top of the power steering bottle (how about that for a brilliant piece of engineering...!).

As far as I have observed, most if not all all-aluminium engines will dissipate a lot of heat when running.
Turbo aside, I'm not sure the engine itself (block+ head) on my S2 generates any less heat than the turbo.
For sure the turbo being located where it is contributes to heating everything, but let's widely speculate that Porsche put it there partly because they intended to keep on with the 4-2-1 exhaust manifold of the NA engine to emphasize on low down torque and make the car really easy to drive. Considering something like the Audi 5 cyl engine, no such exhaust manifold can be made, even less something like a twin scroll exhaust manifold. But I'm wandering way off topic here...

The air flows down over the clutch bellhousing, which is why it's important to run both undertrays so make sure it's sucked down and out properly, short of trying oulet vents in the bonnet.

 

[scam75]

ORIGINAL: 944Turbo

ORIGINAL: 924nutter

I've just looked it up and the max boost is 0.82 bar or 1.82 on the gauge, so I can live with that. I am also happy that as standard the boost is expectd to tail off by 0.3 bar at the top of the rev range.

I reckon if the guage is going off the scale it has been modded, I suspect a small brass bleed valve in the boost line that runs down to the wastegate (from the cycling valve under the rear of the intake manifold) and chips.
Tony

I had a similar set-up when I bought my car, turned out to be exactly that small brass bleed valve and a superchips ecu chip. Still had 2.5 bar fpr and made about 14 psi boost and over 270 bhp. All now removed in favour of current mods but car ran 10 years + with no issues on the old set-up.

Stuart

 

[944 man]

ORIGINAL: TTM

ORIGINAL: George Elliott


but is it my imagination, or are these cars too hot under the bonnet?

Porsche vented the engine bay of the 924 Carrera GT and 968 turbo - both were high performance turbo applications.

Many of our cars have equal or greater performance than these, yet no engine bay cooling.

This results in Higher Oil temperatures, water temperatures, heat damaged wiring looms, fuel flexi hoses, manifolds....?

I don't think there is any real engine bay venting for these two cars, as the scoop on the CGT feeds the intercooler that's above the engine, and the left inlet on the 968T hood cools down the top of the power steering bottle (how about that for a brilliant piece of engineering...!).

As far as I have observed, most if not all all-aluminium engines will dissipate a lot of heat when running.
Turbo aside, I'm not sure the engine itself (block+ head) on my S2 generates any less heat than the turbo.
For sure the turbo being located where it is contributes to heating everything, but let's widely speculate that Porsche put it there partly because they intended to keep on with the 4-2-1 exhaust manifold of the NA engine to emphasize on low down torque and make the car really easy to drive. Considering something like the Audi 5 cyl engine, no such exhaust manifold can be made, even less something like a twin scroll exhaust manifold. But I'm wandering way off topic here...

The air flows down over the clutch bellhousing, which is why it's important to run both undertrays so make sure it's sucked down and out properly, short of trying oulet vents in the bonnet.

I suspect that the bonnet vent on the RS did help to keep underbonnet temperatures under control by keeping the heat from the intercooler out.