FAO: Ian & other big BPH/turbo users

[Fletcher]

currently in the process of a 2.0turbo conversion, and i just wanted to know how do you guys keep all the power down?

also as the car is gonna be extremly light (FULLY striped out) will i suffer from major handeling problems with the back end being so light (running Bilstien PSS9 coilovers)??

any help/info would be great

[Fester]

Ian normally has a brace of DVD players, VCRs and TVs in the back from Rumbelows

[Fletcher]

:D any help?

[Ian]

:lol: @ fester

a good LSD wil help as will rose jointed tie bar brackets (anti dive kit)

things like rose jointed lower arms and excentric top mounts (spelling?)should also help, with back end being light if runing disks you will need to change the compensators.

CP is prob the best bet for this for proper tech answer

[Jim]

It's going to be difficult for you to keep the power down, you'll be getting alot of wheelspin if you try and floor it all the time. An LSD will help with this.

As regards to handling...thats the great debate. In truth us smaller engine owners probably try and use the handling issue as an excuse to try and look for a flaw with the 2.0l conversion. The 2.0l conversion is a common choice for an instant power increase. The handling can't be that bad I suppose as so many people have done the conversion :roll:

Jim

[CP]

I don't find the backend being light a problem at all. The only time I notice the back end reacting is under extremely heavy braking when it becomes a bit twitchy and you feel that if you wanted to do you could flick it round into a rally stylee tail out slide. If it steps out at all which is very rare it seems relatively easy to catch? I have drilled discs on the rear and I haven't altered the brake bias from std. I dont really feel any need to - it seems to work OK.

The front is a different story tho. From what I've read a 2.0l and F20 box adds getting on for 50 kgs over a std 1.6/1.4 8v.
These is gonna making braking more of an issue but TBH even with a 2.0l in you are still gonna be a pretty light car. I would suggest trying a bigger kit on the front say 280mm plus discs and add some decent comp 4 pot calipers ( they will be lighter cos made out of ally) Hopefully this will mean that a higher % of your braking effort will be put to the front to compensate for the xtra weight.

As regards traction, as Ian eluded to there are 2 courses of action that I have found made a huge difference to cornering and exit speeds.
1. Fit some sort of LSD (limited slip differential). I'm using the quaife ATB unit which automatically transfers drive away from a wheel losing grip to the one that isn't. Some people dont like them cos they can be a bit snatchy from side to side as they hunt for grip but it does help traction enormously. Or you can get a plate LSD of some sort which can be adjusted for the required amount of slip. They need some maintenance tho from what I hear- ATB's dont.
2. Fit the rose jointed tie bar kit etc as Ian said. This effectively lowers the point on the front chassis cross member that the wheel assemblies pull from under acceleration. This point is below the centre of the wheel and so has the effect of pulling the car down. This negates a lot of the lightening effect that a std suspension creates under heavy acceleration as it tends to allow the front to rise up. Similarly rose joints alround remove all the give in the suspension that encourages lack of grip throught the movement of major components. Under braking the reverse effect is true ie anti -dive.
The tie bar kit also allows for adjustment of castor. I've increased castor ie pulled the wheels forward cos I noticed that the touring cars have a lot. It improves turn in and makes the steering more responsive. I have a quick rack steering as well which greatly helps the accuracy of steering particularly when you are travelling very fast and turning in sharply to corners on the limit.

The final part is uprated springs and struts. I dont know too much about this as yet but I think most respectable brands that do a competition style coilover for a Nova will be OK - the spring ratings will be ball park. Some are made less well ie Avo. - avoid the cheap ones is the best advice ( I should know I bought Avo :oops: )

The net result is car with minimal body roll, precise handling and the ability to put the power down without mental wheel spin. The down side is that it'll be rough on anything but good smooth roads.

I've got a 1.4 16V with this sort of set up and wheel spin in the dry is relatively rare. However you will always encounter more of these problems with a 2.0l cos of the low down torque it delivers. So the final "mod" I would suggest is to teach yourself to always aim to feed the power on smoothly.

[Fletcher]

thanks a lot, help'd a lot :wink:

have a set of bremsport 4pot's on front(295mm) and astra gsi rear disks and have also gone with bilstein PSS9 coilovers

i have seen many good reviews on the quaife ATB, gonna look into it more

thanks

[CP]

Forgot to mention tyres.

There is no doubt that the more power you have the more important tyre choice is.
Wider lower profile tyres tend to resist lateral forces better but lose some of their advantage over uneven and variable surfaces. Softer compound tyres usually grip better but wear more easily. I would say that a good sporty tyre from any of the major manufacturers - Yoko's, Michelin, Toyo and 1 or 2 others will be the best compromise for general road use.

[andybishop]

Quaife LSD is defe worth getting with a LET engine'd nova, will not totally get rid of the wheel spin though!!

If you need any info on fitting the engine give me a shout.

[Rick Draper]

Are the billys Coilovers all round? I really need to get rid of my nasty avos and its come down to either billys or ledas. You got any pics of them fletcher? Rick