48 replies to this topic

[Steppenwolf1980]

Well, so if you don't use the car a lot, why thinking about more power? No, seriously, I believe that the wheels on the car are the absolute number one thing to change when it comes not only about performance increase, but also about safety. The cheapest way to make the handling better is to put 195er tyres on front, I think the Yokohama S-Drive do have an official permit of the manufacturer to fit on the narrow 5.5 inch rims. Better would be a broader tyre, of course, but then you need broader rims. I use 7.5x17 inch rims in the front and 9x17 inch rims in the rear, they are the DTC model by ATS and equipped with Toyo 888R semislicks in 215/45 front and 245/40 rear. The handling is imho perfectly balanced now, neither understeering nor oversteering (only if provocated). But other good couples are 205 front + 235 rear or 215 front + 235 rear. Cheapest way is by putting another two original rearside rims (7.5 wide) in the front, but you need 15mm spacers on each side to have them run freely. Of course the genuine rims are quite heavy and a 235 or 245 tyre surely works better on a 9 inch rim. It always depends on how much performance you want, how fast you want to go and how much money you'd like to spend...

[Vespa]

Well the fact I use it so little is the reason I want it to go faster, I want the thrill! I have previously built a bike engined lotus 7 replica with 330bhp/tonne and that was very quick so I want the vx220 to do similar I've noticed a lot of people change their fronts to 16" but I don't like the look of them under the wheel arches. I like my gloss black 17"s so would like to change them for something similar looking only wider. Is this what u have?

[Steve B]

I run a GT2860RS on my 1.8 mx5 currently at 11 psi with a purposefully weak actuator spring (as the stock engine couldn't take more), it produces a graph like this :-



I spoke to Owen Developments the main UK Garrett distributor and they said it wouldn't hit peak efficiency until 16/17psi so scaling things up that should give me about 310bhp on a 1.8 engine that as n/a only produced 130bhp. I'd hope that the much more recent Vauxhall engine would flow better and give better figures.

[Vespa]

Thanks for posting the graph up! It does make it easier to picture what the car would be like to drive. Perhaps I'll speak to owen developments and see if they have any experience with the VX220 as I like the fact I have good mid range power but your gt does t seem to spool up until much higher in the rev range. Thanks again!

[Steppenwolf1980]

11psi is equivalent to 0.75bar, just had to check. That's the half of mine, it's running at 1.5 bar overboost I know that the DBilas-powered Turbos (Ex-N/As) also run with about 10 to 11psi because they have a higher compression than the 2.0 engine. @Vespa: Well, my ATS rims don't really look like the genuine ones. They are a lot lighter and they also appear like that. Here is a link to some pictures, unfortunately the Group Buy doesn't seem to take place. http://www.vx220.org...ats-dtc-wheels/

[Vespa]

I'm liking the look of those, and in black they would look great on my silver vxt. Something else to add to my summer shopping list I think!!

[Nev]

Vespa, have a good read of my engine build blog HERE as it covers a lot of background info that you need to know...

[Vespa]

Vespa, have a good read of my engine build blog HERE as it covers a lot of background info that you need to know...

Nice one cheers Nev! Looks like you've done a lot of research there making some very interesting reading. Is Nipper back on the road after the conversion yet? (I haven't had time to read to the end yet?)

[Nev]

Nope, the engine is about 1/2 way through the rebuild atm. Obviously my car is still running with its original engine ATM, though I can't drive it at the moment. An approx time it might be fully build and ready to drive hard is June.