Cheap ways of reducing charge temperatures?

[Tannhauser]

I've been following recent discussions about underbonnet and charge temperatures (including Jake's blown engine thread) with interest. My EGTs seem high and though I understand that this may be related to timing, I'd still like to address heat-related issues.

Could I achieve any worthwhile reduction of temperature for, say, £250ish? And if so, what might be the best way of doing this:

Louvres? (£100 for 20 plus bonnet respray)
Scoop?
Air box (MVP do one for $189)?
Thermal wrap for downpipe?
Intercooler cover?
Any other ideas?

I'm running a T61 single with a FMIC (that is probably a bit tired), water injection, turbo blanket, j-spec bonnet.

Edited to add: engine bay appearance isn't important to me if someone has an ugly but functional solution.

Thanks

Cliff

[hadyn]

Would a bonnet scoop actually help bring charge temps down?? I doubt it, but it obviously would be good to bring under bonnet temps down

[adi2009]

IMO, the best bet would be thermal wraps for the downpipe. But again is there no way of getting some sort of turbo blanket for the twin setup like some people do for the single???

[JustGav]

I'm sure you could get a big turbo blanket made, and put it over where the shield is currently...

This would work with a bit of thermal wrap...

I know JohnK made my blanket, perhaps he could make something that would cover the twins..

Gav

[Alex]

Have you thought about making a hole in the filler plate below the filter and ducting air up through it from the old SMIC hole? This could be achieved most cheaply with a bit 90deg drainpipe.

A heat shield (double skinned ideally) is the best idea for stopping the hot air being injested...then as per above you just replace the hot air with a cool ducted breeze.

Thermal wrapping for the exhaust is only about £20 so it's deffo worth doing. And personally I wouldn't be without my security..er...turbo blanket.

[adi2009]

There was a discussion about intake systems and which would ideally be the best 'cold air' system, might be worth checking out if you are interested

http://www.mkivsupra.net/vbb/showthread.php?t=40870

[Tannhauser]

There was a discussion about intake systems and which would ideally be the best 'cold air' system, might be worth checking out if you are interested

http://www.mkivsupra.net/vbb/showthread.php?t=40870

Oops! Missed that one. Thankyou for that - and to others for their suggestions.

[SimonB]

Proper ducting for the FMIC would be my suggestion. I.e. an undertray if you haven't got one already. You have a GReddy E01 if I remember correctly? If so you can monitor intake air temp if you have the external signal harness by connecting it up to the relevant wire on the ECU. That way you can see what effect your changes have.

[Chris Wilson]

EGT's are far more a function of mapping and turbo sizing than intercooling, to give a meaningful answer I need to know accurate full boost, at peak torque RPM, mixture readings and intake charge temps and exhaust gas temps measured within an inch of the port at the same RPM and load. Don't confuse intake air temps with EGT's. Both need individually measuring. If you are seeing over 900 degrees C EGT's I'd stop pushing the car until it's addressed!

[TLicense]

Chris,

I've read, possibly in a number of places, that reduction in inlet temps is proportional to reduction in exhaust gas temps. Any truth to this?

[Tannhauser]

EGT's are far more a function of mapping and turbo sizing than intercooling, to give a meaningful answer I need to know accurate full boost, at peak torque RPM, mixture readings and intake charge temps and exhaust gas temps measured within an inch of the port at the same RPM and load. Don't confuse intake air temps with EGT's. Both need individually measuring. If you are seeing over 900 degrees C EGT's I'd stop pushing the car until it's addressed!

Ah, now, this is very interesting. I knew that EGTs vary as a function of ignition timing (with less advance cprresponding to higher temps, iirc?) but I had assumed, like others that a small rise in intake temperature would raise EGTs significantly. However, given that hugely modified mkivs seem to run fine (i.e.non-destructively) in the furnace temperatures of Texas and elsewhere, what you're saying makes sense to me.

The other reason I had for wanting to lower intake temperatures was for performance. The car is very noticeably more responsive in the cooler months, so my simple-minded train of thought was to see what I could do to simulate Winter conditions.

I don't have access to most of the information you suggest. The temperature sensor, for better or worse, is located immediately post turbo. EGTs here reach 700+ under load. I am mindful of the fact that runner temperatures may be significantly higher, so I don't push the car for very long at these temperatures. In any case, I have some other issues that prevent me from pushing it at the moment. I am also presently running a maximum of 1.05 bar of boost.

Thanks, Chris, and btw I'm in the process of emailing you on an unrelated issue.

Simon, I'll look into the E01 intake temp thang. I've no idea whether I have an undertray. I'll take a look. If not, I have a tea-tray and some sellotape standing by.

Cliff

[JohnA]

...but I had assumed, like others that a small rise in intake temperature would raise EGTs significantly.
Why significantly?
It's usually around 1:1