FMIC's, 3" downpipes and boost threshold.

[baka]

Hi ya,

Could yous guys who've fitted a front mount and/or 3" downpipe clue me in on a few things please?

One of the things I love about the 1.8t after owning a couple of fast Jap cars (and a Volvo ). Is the really low boost threshold.

The boost's starting to ramp up around 1800rpm and is doing something useful by 2000rpm.

This is a characteristic of the car I'd hate to lose. Even to the extent that I'd forgo some horsies to keep it.

So I was wondering how much does fitting a front mount affect the boost threshold and lag?

And to what extent, if any, is this helped by fitting a 3" downpipe?

Thanks. 

[paultownsend]

I know all about this!
3"DP will benefit things. If anything it made it spool even quicker.

Then I fitted a THS FMIC. Even though it possibly has the shortest pipework, it's a massive cooler so had increased the boost character, and powerband up further up the rev range.

To compensate this I have purchased a ko3s! 

[baka]

Hi Paul, thanks for the input. 

This is what I was worried about. I don't really want to push the spool point any further up the rev range.

Sounds like just going for a 3" downpipe and a better SMIC with a slightly bigger core might be the way to go for me.

[Bandit127]

Are we talking about a 18t? What engine code?

If you are after torque then consider a remap on a standard engine.

My mate's AUM now makes more torque than the old peak all the way from 2,000 rpm to the redline.

Peak torque point is up from 2,700 to 3,600, but it really kicks from about 2,500 at which point it is already making 15% more torque than it used to. Total torque increase is nearly 40%...

It has transformed his car. For about £250.

[baka]

Hi ya,

A remap is definitely on the cards! Once my insurance is up for renewal in July, I'll be taking it down to R-Tech for some remap goodness.

What I'm kinda trying to figure out is how going full stage 2 affects driveability.

I like power (who doesn't!). But if it means the turbo spooling 500rpm higher up the rev range. I'd probably stick with stage 1.

That or go for a decent side mount and downpipe to keep the spool lower in the rev range.
 

[Scott D]

Fitting a downpipe and ported exhaust manifold will help and a remap will reduce amount of lag from fitting an FMIC

I noticed hardly any with a Forge FMIC on standard map nor after custom mapped

[Dalo Harkin]

You will always get more lag with an FMIC as there is much more pipework than an SMIC, how much you will notice it depends on the diameter of the pipes you use, and the turbo, a K03s seems to cope fine with 2.5" pipework and give very little lag.

[baka]

Thanks guys. 

I might pick up a s/h front mount and give it a go.

I can always change it for a side mount with a bigger core if the lag bothers me.

[Scott D]

FMIC is a much better option than side mount for efficiency and lag is not that noticeable even with 2.5" pipework. Twinpass has less pipework but single pass will be much better for flow and hold top end power for longer with not much more lag.

[baka]

FMIC is a much better option than side mount for efficiency and lag is not that noticeable even with 2.5" pipework. Twinpass has less pipework but single pass will be much better for flow and hold top end power for longer with not much more lag.

Cool thanks.

TBH if anything I'd go for a twinpass, just to avoid the epic amount of piping required to plump in a single pass cooler. 

Looking at the Forge/THS ones. The difference in volume between the stock side mount set up and their front mounts, isn't as big as I'd anticipated.

I'm not chasing big numbers, the bank account wont take it.     

I'd be very happy with 240hp.