Any suggestion how to reduce the turbo lag ? Someone suggest me putting header on, or get a 993 6-speed transmission ! Just wondering how you guys did ?

 

Several:
1)I have B&B headers and they are shorter to the turbo so the gas is hotter and you get a much better spoil up.
2)Get a performance back box (after the turbo) or even cat by pass- that makes a hell of a difference!
3) havent fitted it yet but the manul/electronic boost controller seems to work- the manual one is 10quid and it stops the wastegate leaking air up till your boost limit (e.g 1 bar) then opens the gate then.
4) HF turbo- havent run the car yet but these spoil up quicker.
5) EFi - expensive but FYI

Probs some more ways as well....

 

Cheapest method - floor the gas pedal sooner than you would in a NA car

More seriously you can always try the follwoing 2 steps they are easy and cheap:
1 - Buy a new Bypass valve ,it will keep the turbo from stalling during gear changes.
2 - Buy a race cat or remove the cat or empty you existing cat. Definitly helps and isn't to expensive.

I have done these things and it helps a lot but and I am looking into shorter gears or a 6 speed gear box to get rid of the remaining lag. I think the whole package would do the trick together with a RS fly wheel.

Finally, the best method is to call imagine auto and get EFI

Honestly if it wasn't for track use and lap times I would keep some lag, it's part of the car's personnality !

 

Several things, headers. They will reduce spool times why? Well the factory system has 2 elements to it. It is long and it is restrictive. The system currently on the car has to come around the back of the car (towards the front) then around the side where it then goes under the bumper and picks up the turbo. Turbos need hot expended gas to spool up. The longer the pipe the longer it takes to get to the turbo, the longer the spool time. Headers reduce that length by 4 feet causing the header to dump right to the turbo instead of taking the scenic route.

The other issue is restriction. There are two spots that are restriction. The cat, and the collector. The collector where the pipes come out of the manifold can pick up velocity or speed if you will by using a Burns style collect. This is what you hear people calling a triangular collector. It merges the air in a way that it scoops and causes it to speed up as it comes out of the collector. Again, faster air to the turbo.

Header alone will not add a ton of HP. They do reduce that 4 feet of pipe and if used in conjunction with an entire system will reduce 45 lbs of un needed weight. They will reduce spool times by 800 +/- RPM.

The next c heap thing that will help, a 1 bar spring. It will allow the wastegate to stay closed longer instead of cracking earlier. A boost controller is a smarter way of controlling that and will also adjust based on several factors to keep correct boost.

 

Thanks for all the informations !!!

 

Cat bypass made the biggest difference for me followed by headers. This may have been because the cat had become blocked from a rich running engine, but the difference was massive.

 

Having a Cat bypass, does it means that we have to put back the Cat for the yearly MOT test , is there other ways to go around ?

 

don't worry about MOT. mine passed. Adrian's car even passes w/o mufflers!

 

how loud do the 3.3 turbo 2 s become once the cat is by passed ?

 

There is not a ton of resonance but it is loud!

 

I am currently running cat by-pass with stock muffler.
A couple of friends are running race cat or stock cat without muffler.
At idle there is a big difference in sound, much louder w/o muffler.
But at full throttle we are all at 95db at the straight away.

That has led me to believe that the turbo is "splitting" (not using the right word) the sound making it less of an issue and that the design of the wastegate pipe is the major concern when looking at total sound volume at full throttle.

I hope I'm right, otherwise I will have to do something for next year since I am going to run by-pass cat and by-pass muffler and need to stay at 95db.

Edit:
I love the sound w/o muffler, it's really mean!

 

My HF turbo is actually spooling slower than the stock K27, it was the seat of the pants feeling but also turned out to be the case when logging it. I have a graph to prove it but can't upload pictures. If I remember correctly the difference is 200 or 300 rpms to reach full boost.

I should say that I haven't checked the actual spooling time, only compared the revs to reach different boost levels, in my mind that would be more or less the same, but I could be wrong.

Having said that, I am not going back to the stock K27, I believe the HF turbo overall makes my car faster even on our relativly short tracks here in Sweden.
The spooling is also more predictable, which shows on the graph, the HF is has perfect logarithmic curve, the stock K27 curve is more like "nothing" and then "everything". Which makes the HF an easier drive on the track.

You can also tell that the HF is giving full boost all the way to redline, which isn't the case for the stock K27 where boost drops slowly with rpm. So HF gives more power for sure at high revs.

Perhaps somone could help me upload the graph ?

 

For my daily usage, the stock turbo is more than enough, just when going on the track, seems like the car is too lean, brakes are too soft ( but no fade ), and the turbo is a little hard to control. May be this is the character of single turbo, and that's why it feels so wild on boost......

 

The car is heavy and have a fair amount of hp.
Had lots of problems with "soft pedal" when driving on the track.
Less of that now after installing break cooling, yellow pagid break pads and expensive brake fluid.

Because of the turbo lag it's a handful in the corners, but you get your reward on the straights

 

You need a lot of mods to make this car really perform on the track, ask Staffan and me how we know but then you can make it really fast