Does anyone else find the turbo a bit laggy?

[Julian Edgar]

if you reckon u got a heat soak issue with the standard gti, try opening up the guard behind the intercooler so air flows through the turbo and out through the wheel well. i tried searching this forum for a ho- to (im sure i've seen it here before) but i couldnt find it

I think you need a very big exit vent for it to be really effective. See the end of Browser Warning for my experience in trying it on a S4.

[Johnbu]

Just wanted to say I always enjoy reading your articles Julian, no nonsence for the real world.

I think your review of the Astra Turbo back in 2003 was one of the major reasons I purchased my Astra Turbo.

I've since purchased a Golf GTI to sit along side it.

Back in 03, the Golf GTI was way lagging in performance (compared to the Astra), but the 2005 Golf GTI is better than the Astra, in terms of refinement & overall performance (except for fuel economy).

Turbo's have come a long way, for the better.

[noone]

I think that was the Joey mod, did this before I went to a front mount cooler

[pologti18t]

Julian did a few good stories on the qualities that make a good intercooler for a petrol car versus a diesel.

The intercooler is just a heatsink for when you are on boost.... and for most people thats only for short periods (in a petrol car). So an intercooler with mass is good for petrol cars. INtercooler water spray is a good option as well.

I will have to read back to confirm but even Guy_H (apr) says that for stage 1 (155kw/330nm) that the stock intercooler is ok for most people.

[Greg Roles]

Also ducting it / sealing the edges gets you that last little bit.

[noone]

From memory the Diesel cooler acted like a heat sync, the turbo was less so. It is called the Pikey mod.

After a tune you can def feel the soak on a 30 deg day.

[sssstew]

good article Julian, as i had wondered if it was worth doing and you have confirmed for me that its not

[DNA Tuning]

Whilst the discussion seems to have swayed off track a little bit, it is worth noting in this current discussion regarding temperature vs performance, that modern cars will vary the boost depending on various factor, including temperature, in order to achieve a seemingly consistent level of performance, be it hot or cold.

This means the stock ECU program is greatly limiting the potential of the engine on colder days in order for the car to still feel like it pulls strongly on a warm day.

Once tuned, the ECU will attempt to extract as much performance as possible on both cold and warm days, and hence this makes the car feel like it is suffering from heatsoak on hot days. This is definitely a point worth noting, and one that most car enthusiasts would be happy to accept. For the average joe however, they might mistake this difference as something wrong with the car on the hot days when that is not true.

Of course, it definitely helps to have a larger intercooler to cool down the hot charge exiting the turbo's compressor.

[instigator]

Good article Julian!
verry informative!

@DNA tuning: i don't think that youre input about the ECU is completly true...
because if the ECU is limiting the potential of the engine on a colder day to make it feel strong on a hot day,
how come i have noticed ALOT of heatsoak on my stock SMIC?
i should only put my foot down 2 times over a period of 1km and i could feel it building up allready.
this was on my 100% stock Polo GTI.
and on colder days it was noticeably faster as usual, noticed this wile driving against a friend car (atmosferic tuned Fiesta ST)
normally his car was a tiny bit slower, but when it was cold outside, i realy pulled away from him.
and i should mension you that my car was completly stock, no ECU remap, no other things done to it.
i also measured it with a Gtech and Vbox meter, on colder days it was almost a half second faster on the 1/4th mile as on hot/warmer days.

so now that i have installed a bigger FMIC, heatsoak is completly elliminated on warmer days.
it is now that i notice less diffrence in power between a hot or a cold day.
it pulls almost equal on a warmer day as to a cold one...
and for as far as it matters, i still have a stock ECU (not remapped)

so, i don't know if what you said about the ECU, also counts on a polo's ECU..?
but as the polo's are not so old, i diddn't notice anything from the stock ECU limiting the engine performance or such...
maybe it was pure the SMIC that was limiting it's potential, and this was above the ECU's capabilities for correcting it??

thanks for youre input also, i like to learn more and love to argue over things like this...
sorry for being a pain in the ... tho

[Spec83]

The ECU measures intake temperature.... Higher intake temps = less ignition timing to counteract detonation. Once you install a bigger radiator with a bigger surface area the intake temps drop hence ECU plugs in more timing.

Think what John was trying to say was the stock ECU is mapped so that there is little variance between a hot and cold day so joe average doesn't think there is something wrong with their car every time ambient reaches 30deg and starts hassling the dealer.