Steve's said he's running same boost as Alex so I don't see it making much difference to the bhp figures. Unless the head/cam and larger compressor wheel improves engine efficiently. If it doesn't then the only way to get more air into the engine is more boost.

When we say headwork, what's actually been done? Big valves or just ported?

 

Shouldn't a 5mm increase in compressor wheel size flow more air for the same boost? Not being knowledgable on the subject I might add...

Shouldn't a 5mm increase in compressor wheel size flow more air for the same boost? Not being knowledgable on the subject I might add...

 

No, more air means more boost, it should be able to provide more outright boost.

It's interesting. The extra 5mm will result in the turbo flowing more air. However it's not that straight forward. To calculate airflow on a compressor wheel map you have to work out the pressure ratio your using. You also need to calculate engine efficiency. Put the two together you get airflow. From this you can see where about on the compressor map you are. So yes the 5mm will flow more but if you are using the same pressure ratio and same e/f then you'll still have the same airflow. To increase flow you either improve e/f (which the bigger compressor may give) or you increase the pressure ratio.

Garrett have a very good guide about on their site.

No, more air means more boost, it should be able to provide more outright boost.

Yeah normally bigger wheels allow more pressure ratio.

If we had a compressor wheel map then we could see what boost its capable off. Problem is the third party wheels don't come with them. If you stick within the garret family then you can check their site of listed.

If anyone wants a read.

http://www.turbobygarrett.com/turbobygarrett/sites/default/files/PDF/Turbo%20Tech%20103.pdf

Different material wheels and top speed

http://www.dieselusa.com/productinfo/BorgWarner%20Titanium%20compressor%20wheels.pdf

Yesterday there was a Golf that has the same spec as mine but with a tubular (and mapped by John also), and it made about 4bhp more than me and about 30ft/lbs more torque!

Just got a fresh log from the golf. We're running f more fuel low down which will explain the difference in torque.

Interesting, it is possible that Steves 65mm wheel is actually slightly too big and is therefore not actually capable of supplying any additional boost without proper head and cam work to allow more flow at high rpm.

Very interesting reading gents!

 

Will report back when I've tried the new map off John

Been having a look over some of my calculations. I recon you'll need 3bar of boost to crack 300 bhp with out going the crazy smoke route. The gtb2260 won't like that lol. But the gtx 60 wheel will like 3.2 bar

Fancy changing your compressor wheel Alex and having it rebalanced and some dssr90's while your at it.

http://pages.ebay.com/link/?nav=item.view&alt=web&id=171768290178

Do tell more....

Would it hack that sort of boost?

Seems like a relatively cheap thing to do other than the DSSR's....

That turbo wheel looks nice!

 

I am still not sure how far I can push my 2566vk wheel yet.  Have been doing 2.8 bar with no issues [yet....]

What's your lag like Jason?

 

I was speaking to a lad on the rolling road day who has a 2566 in a Ibiza purely for a track car, and he said it would be awful for a road car...

What's your lag like Jason?

 

I was speaking to a lad on the rolling road day who has a 2566 in a Ibiza purely for a track car, and he said it would be awful for a road car...

 

1980's turbo road cars were terrible, I don't think anyone gets real lag any more, in the original Porsche turbo you used to be able to count to three before the horizon smashed you in the face.

right thats it im looking for a bigger turbo what do people recommend? 

right thats it im looking for a bigger turbo what do people recommend? 

 

Proper headwork and a performance cam.

Proper headwork and a performance cam.

gtb2260 cant run 3bar of boost so bigger turbo is needed

Thought you had a 65 hybrid?

Has Steve been telling silly pub porkies about his setup? I am disappoint, I thought we were all grownups here.

http://www.briskoda.net/forums/index.php?/topic/351704-map-problem-i-believe

He mentions 65 here. Post 52

Then it should certainly be capable of 2.8 - 3.0 bar.

hmmm i wonder....

What's your lag like Jason?

I was speaking to a lad on the rolling road day who has a 2566 in a Ibiza purely for a track car, and he said it would be awful for a road car...

I drive around it. Use revs if I need progress, otherwise it drives OK low down. Just need revs for power. Was making good boost at 2500 full boost by about 2800, full power to 5200 limiter.

hmmm i wonder....

Just crack up the boost.....but kiss your warranty goodbye at the same time. Pretty much what Alex did lol.

Can't fault Xmans turbos and his service though.

Hey, it's only £800 for a replacement at the end of the day ha ha!

Seems 2.5 Bar is the precedent now!...