99 replies to this topic

[Nev]

Really? Do you expect a sports car without TC to not to wheel spin in 1st gear?

 

If that is genuinely the case then you better restrict your NA down to 50 ft/lb, or better still part exchange it for a mobility buggy, I think they should be safe in the wet.

 

Seriously though, you sound like a good candidate for after market traction control, I've been in a VX with it and it is amazing.

Edited by Nev, 28 December 2014 - 11:46 PM.

[speedster]

come on we know the turbo throws around a lot of weight, its different from an na. As mentioned, keep an eye on the power to weight ratio, what bands work best.

[pete-r]

What will you use the car for? Assume track days because in my view a 400bhp VX for road use would be a little bi too overkill... Personally I would measure up the spend and ball ache of it all carefully. For 3k you could have a 250bhp sc car which in the road is for me the best all rounder, or spend a little more and a 300+ turbo would be in budget. Both options would be tried and tested and the car wouldn't be in bits for ages while you figure out what would be a bit of a prototype. if you want an idea of an sc car I'm in Swansea so pop down anytime.

[speedster]

  Seriously though, you sound like a good candidate for after market traction control, I've been in a VX with it and it is amazing.

I decided against TC... Keeping the brain exercised! Though if I do build big power

[Escy]

I'd use the car for the road mainly. To be honest, I enjoy the build as much as the end result so the hassle side of things isn't an issue for me. Costs spiralling out of control are but I don't think it would be expensive compared to the other options (supercharged or buying and tuning the standard turbo). I'm quite economical when it comes to things like this. I've done engine swaps in the past that have basically cost me nothing after breaking donor vehicles (won't get anything back on an old Saab) and selling off original parts. This thread was to see if the idea is viable. I was half expecting there to be a big reason it isn't possible but nothing has been mentioned. I'd have thought it'd have been done already. Thanks for the offers of taking me out in various tuned VX's. At this point it's just an idea until I can sell my AE86 (anyone fancy a px, it's 270bhp)

[TheRealVXed]

I think the extra weight is probably not a problem for the power... Although no one has put any figures out there about how much it weighs extra?

 

The only thing I would watch out for is the weight distribution.  Being mid-rear and adding say 100kg in the back end, is naturally going to make it even more like swinging a hammer then it already is, and with such a short wheel base you're going to have to be able to catch it masterfully quickly especially with all that power...

 

I would investigate what Slindborg said about the engine height as that might be a show stopper....

Edited by TheRealVXed, 30 December 2014 - 09:58 AM.

[Nev]

I don't actually know what the weight increase of a Saab B204 engine over the NA engines for sure. However, having looked at the blocks, I'd say the short engine would be at least 25 KG heavier, the turbo + external wastegate would probably add circa 15 Kg, intercooler + pipework + water would be in the region of 30 Kg, larger (and longer?) exhaust perhaps 10 KG extra.

 

So an approximate +80 Kg when switching from NA to B204. This is just educated guesswork on my part BTW.

 

Looking at the sheer amount of material in the block (particularily between the cylinders), you can see why these engines can safely make 500 BHP without any internal mods. This "extra weight" must really add stiffness to the engine.

 

If/when my current engine expires I might consider a B204 myself.

Edited by Nev, 30 December 2014 - 10:15 AM.

[slindborg]

Various sites claiming 156kg for the 204 and somewhere said the block only was 20" tall but no head or sump info. The b234 is taller apparently and that's something like 700mm fully assembled

[TheRealVXed]

This "extra weight" must really add stiffness to the engine.

 

Or they just made it out of whatever pig iron they had lying around at the time

 

100kg weight gain then potentially... in proportion to the weight of the VX n/a that is an 11% increase.  Not to be taken.... ahem..... lightly 

[Nev]

Yep, +100 KG sounds a lot on paper. However in practice the torque and power (assuming the OP tunes to approx. 350 ft/lb and 400 BHP) will give dramatic performance increase in the real world over a 100 KG lighter NA with only 150 BHP.

 

I've driven and sat in loads of VXes over the years and the difference between 150 BHP and 400 BHP is monumental. If the OP can do this for just a couple of thousand pounds I'd say he'd have a great little car and at a very effective cost/benefit ratio.

Edited by Nev, 30 December 2014 - 10:25 AM.

[TheRealVXed]

OINK!

 

Edited by TheRealVXed, 30 December 2014 - 10:26 AM.

[Nev]

That American spelling, not English.  Blast them to hell for corrupting our youth !

Edited by Nev, 30 December 2014 - 10:27 AM.

[TheRealVXed]

You "yank"ing my chain?

[Nev]

Really, I believe the spelling for pyg iron is right, it refers to the low grade stuff. For example the "pyg track" in Snowdonia, named after the mines that it used to lead to.

[speedster]

Yep, +100 KG sounds a lot on paper. However in practice the torque and power (assuming the OP tunes to approx. 350 ft/lb and 400 BHP) will give dramatic performance increase in the real world over a 100 KG lighter NA with only 150 BHP.

True but how will it go around corners?

[Nev]

 

True but how will it go around corners?

 

 

Better if you stick wider wheels on it and grippy rubber, many VX enthusiast owners end up doing this (regardless of power) for the grip improvement in the dry.

 

I used to pull a sustained 1.5 lateral G (flat smooth tarmac, V70 tyres, ambient of around 15 degrees) when I last tested my own car about 3 years ago, and since modifying the suspension parts and geo-ing it myself I think this is a bit higher now, perhaps 1.6 or maybe a bit more G. That is considerably more than factory VX even with my car weighting approx. 30 KG more than a factory car.  

As is always the case with tuning, if you increase one thing it means you need to increase others

Edited by Nev, 30 December 2014 - 10:44 AM.

[TheRealVXed]

Really, I believe the spelling for pyg iron is right, it refers to the low grade stuff. For example the "pyg track" in Snowdonia, named after the mines that it used to lead to.

 

it's the first by product of smelting the iron ore .  Chemistry

Edited by TheRealVXed, 30 December 2014 - 11:08 AM.

[siztenboots]

if you use the 2L NA block , aka B206 , this is lighter as it is cast without the balancer shafts in the side , the shafts themselves are about 2.5kg each , plus the chain

[speedster]

 True but how will it go around corners?  

  As is always the case with tuning, if you increase one thing it means you need to increase others

Rolling gear mods certainly assist in keeping powerful modified cars out of the ditch!

[Escy]

I think the extra weight is probably not a problem for the power... Although no one has put any figures out there about how much it weighs extra?

 

The only thing I would watch out for is the weight distribution.  Being mid-rear and adding say 100kg in the back end, is naturally going to make it even more like swinging a hammer then it already is, and with such a short wheel base you're going to have to be able to catch it masterfully quickly especially with all that power...

 

I would investigate what Slindborg said about the engine height as that might be a show stopper....

 

I've seen a picture of a VX220 with an Exige style engine cover, i'd assume something like that would get around any height issues if needed.