Intercoolers

[wrinx]

How much can the standard IC handle before blowing it's sides off?

Are there any FMIC which fit nicely on a Q4?

What power gains can be expected from a FMIC for various sizes?

...just thinking ahead at the moment

wrinx

[arjunior45]

How much can the standard IC handle before blowing it's sides off?

Are there any FMIC which fit nicely on a Q4?

What power gains can be expected from a FMIC for various sizes?

...just thinking ahead at the moment

wrinx

the oem one can handle up to 1,4bar before the plastic part starts to leak from the junction with the alu part.
But you can reinforce it using the metal strips for heavy parcels {do not know the term in English - 'cerchi' in Italian}. It is a common 'mod' in the late '90s and it works.

What is FMIC?

Nick

[q4fatboy]

This is something we have been thinking about as well, would like to move the Intercooler to be more in the centre of the car to get better through flow at the same time.

[wrinx]

Already started on the central vents with a view to this

FMIC is Front Mounted Inter-Cooler...straps are a good idea but I think I want a FMIC instead

wrinx

[arjunior45]

I'm thinking very seriously to go just for the water spray and for a fan like this, avoiding all the trouble with FMIC {which by the way I believe that increase the turbo lag}. See attachment.

Nick

[wrinx]

Why do they increase lag?

wrinx

[arjunior45]

I believe it is related to the major distance between turbine and inlet manifold.

Nick

[Steve Webb]

I think FMIC decrease throttle response rather than increasing lag due to the increased intake length.
From what I have read the standard IC is of a fairly good design, with only a small pressure drop across it. The problem of course are the plastic ends and the rest of the pipework. Also the standard IC is fairly small so cannot deal with the heat produced with sustained boost.
I've opened up the bumper infront of the IC and added the Autospeed waterspray kit. This seems to have helped with intake temp and I'm happy with the results. Now that the battery is in the boot, I want to try and sort out the pipework as I think this will help with the throttle response.

[Evodelta]

If you want to know which off-the-shelf intercoolers fit your car then get out your tool kit and make a mock up to see if it fits, that is what I did (twice) before fitting an intercooler and chargecooler (on different cars).

A proper intercooler needs to meet 4 basic criteria, the first is obvious, it needs to cool the air.
The second: It needs to do this without losing too much of the pressure that the turbo has built up.
The third is where many go wrong, even car manufacturers: It needs to be able to flow enough air at all RPMs so it doesn't strangle the engine.
Fourth - It needs to fit!

If you can find an off-the-shelf item that can do all this and fits then you are well on your way, if not, you have to sit down and design your own.
An intercooler must be sized as per the output of the engine and until you know this and temp test your existing one you don't even know if you need one.....

Bigger intercoolers and FMICs don't really cause lag, it's a falicy, inefficient engines do.

Very few people understand intercooler design.

[wrinx]

An intercooler must be sized as per the output of the engine and until you know this and temp test your existing one you don't even know if you need one.....

Jeeez, is nothing simple on this car

Might have to come back to this.....or get a fan

wrinx

[arjunior45]

you might also consider something like this :


this is the link : http://www.halme.fi/Q4/mods.html#Spray

Nick

[Steve Webb]

Bigger intercoolers and FMICs don't really cause lag, it's a fallacy, inefficient engines do

But surely the intercooler and associated pipework are considered as part of the engine overall?
My point was that by using a FMIC you are going to have to (usually) increase the length and complexity (twists&turns) of the intake to actually plumb in the IC which in turn is going to have a detrimental effect on the way boost is transfered from turbo to plenum.
Not turbo lag as such, but as the turbo builds boost it has got alot of air upstream of it to compress/move before the the boost produced by the turbo reaches the plenum. Giving the impression of turbo lag or poor throttle response.

I thought one of the popular mods amongst the Grale community was to shift the bottom of the standard intercooler forward a couple of inches to get a straight run from the turbo to intercooler supposedly giving better response.

I did some experiments with IC's after reading this article Autospeed IC waterspray kit
measuring IC temp etc, before and after fitting one of their kits. For what I need from an IC it suits me fine.

[wrinx]

So...improving the airflow and setting up the standard water spray will help.

Although I really like that slightly larger custom IC

wrinx

[arjunior45]

Although I really like that slightly larger custom IC

wrinx

if you visit his site {link} you'll see that he uses water spray with his custom made IC!!!

[Evodelta]

But surely the intercooler and associated pipework are considered as part of the engine overall?
My point was that by using a FMIC you are going to have to (usually) increase the length and complexity (twists&turns) of the intake to actually plumb in the IC which in turn is going to have a detrimental effect on the way boost is transfered from turbo to plenum.
Not turbo lag as such, but as the turbo builds boost it has got alot of air upstream of it to compress/move before the the boost produced by the turbo reaches the plenum. Giving the impression of turbo lag or poor throttle response.

I thought one of the popular mods amongst the Grale community was to shift the bottom of the standard intercooler forward a couple of inches to get a straight run from the turbo to intercooler supposedly giving better response.

I did some experiments with IC's after reading this article Autospeed IC waterspray kit
measuring IC temp etc, before and after fitting one of their kits. For what I need from an IC it suits me fine.

Yes, you aren't far off the mark there, what I am trying to point out is that a bigger and properly designed/sized intercooler isn't the thing which contributes to the lag on an engine like many will tell you, it is influenced by any or a combination of the following:

Cams
CR
headwork
turbo (type and size)

And probably a few more I forgot. Remember, we are talking about a very old engine and its ancilliaries here, It can be modernised though to good effect.

When a decent sized turbo starts to spool the air it emits will fill a transit van in seconds, a larger intercooler won't effect the lag much.

The mod that the integrale guys do is indeed to move the IC forward, but it is to get a straight run into the turbo (from the air filter), not from it.

The Autospeed intelligent water spray is the best you can buy, it's a nice piece of kit if you want to stay with your OE cooler and you aren't chasing big power, water spray will only net you 8% max reduction in temps though. What kind of temps did you record? I once saw 65'c inlet temps on track with the OE cooler, you wouldn't normally be able to get that on the road though. I managed to cut them down to 35'c with a better cooler, cutting intake temps and allowing much greater flow through the cooler netted some good gains in power.

In intake piping bends spoil flow, straight runs don't.

I know it's horses for courses and about how far you want to go with your car though.

[wrinx]

Well, that's saved me a few pounds then

Get the waterspray sorted and move the IC to line up with the turbo, perhaps fit some metal straps

Might look at a custom IC in time

wrinx