rosswalker

Any advice on how to keep the temperature down, so that the charge temperature is low, and the intercooler does not suffer from heat soak as much?
Is there any way of improving the turbo heat sheild? Making a cold air fed heatproof box for the indiction kit. I would be interested if any one has attempted anything like this, and if the mods were effective?
I have an MY99 with Tek2, Blitz induction, and Graham Goode exhaust with sports cat.

P20SPD

iTrader: (1)

Best way is a FMIC IMO.

Razor2001

Looking at the standard JDM STi-7 induction isn't it similar to a cold air ram induction ?

The entry for the air is at the front of the car right under the bonnet lip edge at the front and then the tube back to the air filter box is sealed from there....is there alos a tube from the air filter box that goes into the wheel well to suck in cold air ?

I would have thought that the above stock setup is quite good and can not be improved on much with a mushroom etc filter in the engine bay or even a cold induction to the wheel area ?

Thoughts ?

Cheers,
Ray

Razor2001

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Razor2001

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Bob Rawle

P20 hit the right note, fit a FMIC, no other way to do it, even at my current spec level I still only get 10 degrees rise on a 1800 to 8000 rpm full throttle run in 4th (or as far as I dare go in 5th) With a top mount, holding 1.2 bar up there kicked charge temps into the high 50's at times.

pat

Fitting an FMIC allowed me to place an air box where the TMIC should be, this has a very positive effect on charge temps for several reasons...

a) It's an FMIC so the core and charge air surface areas are much larger, improving cooling of adiabatically compressed air

b) It's fed from outside the engine bay, so the intake temps will always be at ambient, unless stood in traffic for hours, but then anything would heat soak under these conditions

c) When moving forward air is pressure fed into the air box and down into the turbo. Given that the air pressure into the turbo is raised, the pressure ratio needed to achieve the desired boost pressure is less; the compressor is doing less adiabatic compression on the air, it may well be operating in a more efficient region of the flow map and the isobaric temperature increase will be proportionately lower at the deisred boost pressure.

All in all, the setup works really well, the throttle response once you're moving is unbelievable (you have an immediate supercharging pressure to play with even before the compressor spools up).

I ran a similar setup on Knockhill. I was having such fun I stayed out for about 1 hour and 20 minutes in a single session, pretty much draining the fuel tank in one hit, yet the datalogs showed no more than 30 degrees air charge temps

Cheers,

Pat.

john banks

Pat, any idea how much positive pressure this setup was making?

Razor2001

Any thoughts on my above post about the factory induction ?

Cheers,
Ray

dowser

Re. STi7 OE induction - does it still have the gourd like resonator inside the wing? This is a big restriction on the classics....

Richard

P20SPD

iTrader: (1)

AFAIK they do.

Razor2001

What is the 'guard like resonator' and what does it do, can it be removed and still maintain a safe induction ? ie: Is it just there for nooise control ?

Cheers,
Ray

Stuart Knight

iTrader: (2)

Ross,

I replaced the dummy air vent above the induction kit with a scoop to try and achieve what your after. Don't know if it works, but in theory it should.

Stuart

rosswalker

Im not sur that I buy the idea of using ram air methods in to the cone, as the charge temperature is determined by the efficiency of the intercooler, i.e you could supply the cone with ice cold air, but if the intercooler is hot, the cool air going in to the cone will get warmed up by what is effectivly the an "interwarmer!". The key must surely be in preventing the intercooler becoming to warm. This points to a front mount I/C. I had one of these on a GTiR. I fount that there were alot of negative issues accociated with f/m/i/c's. I would rather find a way of making the top mpunt more efficient by finding ways to keep the under bonnet temps down, and therefore making the interwarmer an intercooler.
Any views on this?????

P20SPD

iTrader: (1)

No one i know of has had any issues with FMIC on their Scoob other than some marginal fitting problems.

CarMan

P20SPD - not more lag?

MorayMackenzie

Ross,

Read pat's post. He explains the advantage of ram air quite nicely. In short, the less work the turbo has to do, the less heat it puts into the charge... therefore the less work the FMIC has to do. So if you have an inefficient I/C (a seperate issue to solve) then you will be asking it to do less work, so it should yeild lower intake temps.

Moray

Edcase

Check out the third one down. APS top mount...2.4 times bigger than standard.

rosswalker

The larger APS intercooler looks great, but just because its larger wont make it hugely more effective as it is still positioned in the same, warm place as the OE I/C. The both have the same capacity to absorb heat. and therefore heat the charge. And so the quest goes on.... The key to making any top mount efficient (regardless of core size) must lie in finding a way to keep the under bonnet temps down. or insulate the underside if the top mount some how. Then you would get the cooling fx from the scoop, without the as much hot air rising in to the unederside of the I/C.

CarMan

No-one find more lag from FMIC's then?

john banks

Most of the lag is influenced by turbo selection IMHO although you will get slightly more lag with a FMIC, sometimes it is so little that you can only tell be measuring it not from seat of the pants. However, with an unsuitable turbo I had more lag with a TMIC than I had with a suitable turbo with a FMIC.

Floyd

iTrader: (9)

Pat, positive pressure - are you sure?????

At the very best I think you'll reduce the effort marginally by reducing the vacuum a little before the turbo intake. You'd probably be travelling at supersonic speeds to achieve positive pressure.

Isn't it more likely that with the air box so close to the turbo the response is better through less drag in a long intake tube?

If I had a FMIC then I'd lose the scoop and reduce drag significantly (drag goes up with the square of speed or something), replace it with a flush mesh.

Underbonnet temps once above 10mph aren't much more than 1 or 2 degrees above ambient. If you keep the top mount then you're better off tilting it, splitting the flow and misting or better still, getting a larger TMIC.

F

CarMan

John - What would you say is best turbo/fmic combination then.

pat

I never actually had a chance to measure the positive pressure, but just as a guide I had a carbon fibre scoop, and one of the bolts was making a mess of the filter element, so I removed it. When travelling at 70 MPH, the rear of the scoop would lift off the bonnet by a good 1.5 inches Try bending a carbon fibre scoop this much and you'll realise it takes a lot of effort!

I doubt that the proximity is responsible, a previous setup had a cone filter in the same place, but not sealed against the bonnet / scoop, so the intake piping was the same but no pressurisation was possible; there was however a noticeable difference between the airbox and the cone filter!

In order to minimise the heat soak of the TMIC from the engine one could construct a carbon fibre cowling that sits under it and vents the air down both sides of the gearbox, but the cost of such an item would probably make an FMIC seem quite cheap Especially when you consider that it cannot help when the car is travelling, and you're still limited to the stock core size, and awful end cans...

Cheers,

Pat.

Floyd

iTrader: (9)

Pat

At Idle there is about -7psi+ from the engine in the inlet manifold, if we measured the inlet pipe to turbo pressure the this should be the same at idle. Of course when on boost the inlet manifold will be under positve pressure but the turbo inlet pipe will be under greater negative pressure. I suppose if you were to provide some positive pressure relative to ambient in the turbo inlet, then the vacuum would be less and the turbo wouldn't be working quite so hard across the range. Maybe you are getting a feelable benefit with this.

What I wanted to say that it is not possible to provide more pressure than the turbo can create just with a scoop arrangement.

The bit I can't understand is that the turbo should spin up much easier when it is restricted, i.e. in a vacuum?

F

EvilBevel

Floyd, I think Pat is talking about removing pressure drop before the turbo. There's a great article on the Autospeed site about "negative boost", but basically with a non optimal inlet tract the turbo has to work "harder" to create the target boost. If you can completely remove that pressure drop (or indeed provide positive pressure) the turbo will be working much more efficiently, even if you aim for the same positive pressure.

PICKLE

So then, anyone going to step forward and start the ball rolling for a FMIC group buy then???

Edcase

Floyd - the APS does all that....its bigger, tilted and split. I wa also planning on getting the I/C spray from an Sti7 too. With an STi scoop. I'm not planning on going much over 300bhp so this should suffice.

rosswalker

What would be a sensible f/mount on turbo selection for a MY99 UK turbo? Has any on experimented for me!!

rosswalker

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