andy97

iTrader: (1)

I believe so :-)

Shaun are your engine internals, rods and pistons stock OE or uprated?

Andy Stevens

Good point. Very impressive to have charge temps below ambient at cruise.

That graph was taken after a stop so the underbay engine temps had climbed, but it does go to show that 'heat soak' is not necessarily the sole preserve of TMICS!

Here are some I took before that run. Unfortunately the vehicle speed sensor was on the fritz initially, but you can infer it from the other data;





It shows a charge temp below what the weather station was saying was ambient, which is a little surprising but not impossible I guess.

Shaun

100% stock and untouched since new.

MrNoisy

iTrader: (28)

My 05 blob STI wasn't making great power on the old top mount, but eventually changed to one of the cheap and cheerful Japspeed FMIC kits, not expecting much.

The car ended up making an extra 25ft/lbs and 28bhp just from fitting the FMIC, no other changes. Admittedly - with a better condition TMIC, I suspect the gains would have been much smaller.

Whilst spool is achieved at almost the same point if you compare the boost graphs on the dyno, torque and power come in around 300RPM later with the front mount than on the top mount, and power delivery feels more gradual and controlled; with the TMIC and the 20g I'm running, the acceleration low down was much more savage when the turbo came on song - you really got thumped in the back - so I can totally understand why so many of the posters are saying the TMIC's are more suited to track and time attack when you want acceleration quick!

StanS

iTrader: (3)

Sorry to interupt !

Great to see my old wagon is still going strong and has been taken to a whole new level Andy

(Other info I found on my last project - I had some cnc machined/flowed/flow-tested heads from Ric Woods on the Hatch and was most impressed - in the grand scheme of things expense wise, a good investment. Not relevant to this thread but thought I'd mention it if trying to get best out of the engine and can't afford full Cossie heads ! )

Andy Stevens

I think Dunc is going to run a project thread on it imminently Stan, we have used it as a test and demo for all sorts of tech, currently for LC, ALS, FFS and traction control.

It still looks pretty stock, but you have to hang on a bit now when the boost comes in.

Also good for data gathering as above. Looks like the intercooler is in the optimal position for our setup.

Cheers

Andy

Henrik

iTrader: (5)

The air flow isn't "kicked up" by the front at all, i think you'll find that on almost all cars, the air flow is nicely laminar on the bonnet, as anything else would create huge drag. There's a high pressure zone right at the leading edge of the bonnet, and a low pressure behind it, which is why race car radiators are often vented here, as it creates a bigger pressure diff across the rad than venting it in many other places (or indeed uncontrolled venting as is the case on many road cars), but by the time you get to where the scoop is, the pressure is probably near enough ambient (or it might even be positive, depending on how far the high pressure zone created by the wind screen extends).

Also with regards to air flow separation etc over the bonnet, at most, there will be a small layer of turbulence across the bonnet (aka boundary layer), but it will not extend anywhere near the top of the scoop, so there is plenty air flow here.


The area of the scoop, then: Radiators/heat exchangers work best when the air flow across them isn't flowing *too* fast - after all the air needs to stay in the vicinity of the heat exchanger to absorb the heat. This requires the air to slow down from the free flow speed, which is why you have a small inlet which extends to a bigger area - this causes the air to slow down, which means that more heat can be extracted for the same amount of air compared to e.g. a front mount. In theory, the air should then be managed and accellerated to the free flow speed again and exit through a small aperture (otherwise it wouldn't be flowing fast, right). A large hole would also create drag.

The above is why a seemingly small TMIC can get rid of as much heat (or more) than a comparably huge FMIC.


Also, with regards to area, when I've been on track with my car, the hotness compared to the distance from the inlet on the intercooler falls rapidly, i.e. on a FMIC it's only really the first part that actually does anything sensible. I'd say in a typical fmic installation, a taller intercooler will give better results than a narrow long one. If you look at how the subaru TMIC is designed, it's actually two relatively tall, but short, intercoolers (the twin inlets at the bottom), so again, the puny size is not a good measure of effectiveness.


Why don't race cars just run a massive fmic intercooler anyway with the whole area in the flow? After all, the absolute cooling effect of this would be better than the relatively more effective "small aperture". The reason for this is that the hole for the FMIC creates a lot of drag, which makes a car slower (and less economical).


When I ran my 03 wrx on a 20g with a TMIC, even in mid summer on a real hot day, the temp was close to ambient after only a couple of seconds cruising. Obviously you'll get heat soak when stationary, but after a couple of seconds you're back to normal temps anyway, so it's not really a big deal unless you're into traffic light GPs. I'm now running a FMIC, which for the money is a great piece of kit, but it does add a lot of weight to the front of the car, which is the most stupid place to put it.


This discussion has actually been quite informative - I might try running on a TMIC again on my new set up (holset hx40 - should be good for 500 hopefully).

StanS

iTrader: (3)

Thanks for the info - pm'd
Will watch out for Dunc's thread.
Best wishes
Stan