Realising V6 Performance Potential

[MyStreetCar]

At present I am working on the suspension development however, whilst the car has improved significantly and is great to drive, I still feel its not quite right yet. I fitted Pedder Sports Ryder springs and comfort gas shock absorbers. I have replaced the front sway bar links with the Nolathane heavy duty kit and fitted Nolathane bushes to the panard rod and upper trialing arms. The car has stock 15 inch rims at present and near new Mich tyres. I am finding that the car still tends to push down into a corner towards understeer at moderate cornering speeds. Also body roll seems excessive. Perhaps readers may have had some success with upgraded / heavier sway bars. I intend to replace sway bars as a meaure of fine tuning the suspension in the near future. Any advice.................??

Peter

 

[HoldenManDan]

Hey mate, i've had a good read of what you're up to on your site. When i bought my VS in july 06, she had a factory V5W (Country pack) suspension setup. This pack included REALLY high front and rear springs, i'm not sure if the shocks were V5W specific, a fairly heavy duty front stabiliser (23mm from memory?), a really light duty rear stabiliser (16mm or so) plus some other stuff .The front stabiliser must be heavier than stock, and the rear, lighter than stock, i'd reckon.

Anyway, i put up with her like this until october when I got her lowered by wholesale suspension. I got King spring super lows on the front (all new struts too), ultra lows on the rear, KYB short shocks, adjustable panhard rod. I've not replaced either front or rear stabilisers. I dont think i'll replace the front as there is very little body roll, and sticks to the road like (you know what) to a blanket. This is on 225-50-r16's BTW.

The rear stabiliser i feel is a little too soft: on hard cornering the rear inside wheel feels like it wants to lift up, like it's oversteering unless i back off. It handles so well as it is, but i think it'd handle better with a stiffer rear stabiliser.

All this said, i'm unaware of how my king springs/KYB shocks compare to the pedders springs/shocks you're running: maybe you need something heavier-duty? From memory, there were 2 shocks options when i was quoted by pedders: "comfort gas" and "sports", and numerous springs options. The sports shocks would give a less "wallowy" ride. If after upgrading front and rear stabilisers to heavier ones and you STILL need a stiffer front end, try a strut brace.

IMHO, upgrading to bigger rims MAY also help, as the sidewalls of 205-65-r15 tyres are rather soft, which wont do the body roll any favours.

Hope this helps, sorry it's so long :bang:

PS Not suspension related i know, but your extractors are running to the stock y-piece, correct? It may be worth getting a mandrel bent y-piece made up to replace it, as the stock one is press bent. Press bends arent as flow-friendly. Just something i saw that you may want to think about :thumbsup: cheers

 

[cruzncommo]

At present I am working on the suspension development however, whilst the car has improved significantly and is great to drive, I still feel its not quite right yet. I fitted Pedder Sports Ryder springs and comfort gas shock absorbers. I have replaced the front sway bar links with the Nolathane heavy duty kit and fitted Nolathane bushes to the panard rod and upper trialing arms. The car has stock 15 inch rims at present and near new Mich tyres. I am finding that the car still tends to push down into a corner towards understeer at moderate cornering speeds. Also body roll seems excessive. Perhaps readers may have had some success with upgraded / heavier sway bars. I intend to replace sway bars as a meaure of fine tuning the suspension in the near future. Any advice.................??

Peter

strut bar, and you can always custom make a rear strut bar?

 

[MyStreetCar]

Hey Holden Man

I appreciate your reply & time taken to express your views & ideas.

Its interesting to hear that the rear inside wheel is lifting on hard cornering, that is usually a problem with vehicles that are fitted with an oversize rear sway bar. As the sway bar is connected to both sides of the suspension, the high vertical load being applied to the outside wheel is transmitted along the sway bar to the inside wheel trying to lift the inside wheel off the road way. This is not much of a problem with front wheel drives however, for a rear wheel driven vehicle already struggling for drive force grip, this is bad news...!!! Once the inside wheel is in the air the show is over...!!! To help balance my car, I may try a very mild increase in rear sway bar size. I will post results when available.

There has been support from other forum readers that a strut brace may help, so I am looking into this option at present. Whiteline Automotive list a strut bar for this vehicle.

As for the Y section of the exhaust, I certainly agree with you...!!! The problem is I am building this car to a budget and the engine internals soaked up more hard earned dollars than first planned. (You know what I am talking about...Hey... It would be so so good to have an open unlimited cheque book)
Anyway, I would have preffered to fit a twin cat exhaust, maybe later on once the rest of the car is finished...???

Having said that, I am pleased with the results of the engine upgrade. 31 extra kW (no fudging) and still naturally aspirated proved that this engine is a great platform for unlimited modification and will deliver the goods beyond most expectations.

Cheers

Peter