Rear suspension advice, please

Pete · Post by **Pete** » Sun Oct 15, 06 9:29 am

Hi there.

Now I have got a reasonable amount of horsepower, I think I need to turn my attention to the suspension again.

Car runs genuine Superstock springs at the rear and long shocks and a pinion snubber.

I apologise for the quality of the picture (not Ron's fault - just not a good enough quality camera) but would value people's opinion. Maybe Drogo has a better picture.

I am concerned about the amount of spring wrap it seems to have - views and upgrade options, please.

I am not prepared to back have the car so options are limited...

Thanks in anticipation.

Dave-R · Post by **Dave-R** » Sun Oct 15, 06 10:15 am

How far from the floor is the top of the pinion snubber? You only want a quarter inch. It looks to me as if you have too much space.

Stiffen the front half of the spring with clamps if there is room or strong insulating tape or gaffa tape or something if there is not.

If this does not do it you are looking at caltracks.

i have to say though. i can't see spring wrap for sure in that photo. It looks as if the back end has lifted off the wheels which is what you want.

Alex · Post by **Alex** » Sun Oct 15, 06 10:17 am

I agree, too much gap and the front half are too lose, get 'em clamped

Pete · Post by **Pete** » Sun Oct 15, 06 10:25 am

Cool, guys.
That run was the shake down run, shifting at 5000rpm.

Beat High TENsion to the eight, & his drugs and my short shifting saw him take the win.

60 foot times down to 1.54.
330 foot = 4.48
Car ran 11.1 @ 120mph

I will re-check the snubber, but I do not think it can go up further at the moment - may have to mod it.

Not sure if the Driver's wheel is up in the photo either....I live in hope...

Blue · Post by **Blue** » Sun Oct 15, 06 10:48 am

Can't see any real problem from that picture, the rear is rising high which it needs to, especilly if you have smaller tyres. With that much suspension rise you could be running out of travel at the rear shackle,if thats the case then you'll lose traction as that happens. Fitting taller front tyres would allow you to lower the front suspension and gain more weight transfer. As others have said, anything you can do to stiffen the front section of the spring will help.

Pete · Post by **Pete** » Sun Oct 15, 06 10:54 am

Thanks Blue, are you suggesting that longer rear shackles may be needed.

I agree about tyre height and after my "moment" mid track (I was shaking 10 mins after) new slicks are top of the shopping list.
Taller front tyres would also be good - have been looking for some narrower front wheels without success of late.

Jon · Post by **Jon** » Sun Oct 15, 06 11:28 am

I'm gonna try clamping mine as per what this guy does..
click ss springs on the side
http://www.carpetperfect.com/

Blue · Post by **Blue** » Sun Oct 15, 06 11:39 am

Yes longer shackles or sliders (my preference) I didn't see your "moment" I assume the car got "loose"?

Pete · Post by **Pete** » Sun Oct 15, 06 1:16 pm

The car did and my bottom reciprocated

Like aquaplaning at 95mph.....

Pete · Post by **Pete** » Fri Oct 20, 06 12:26 pm

I'm gonna try clamping mine as per what this guy does..
click ss springs on the side
http://www.carpetperfect.com/

Good Site, Jon; may be worth investigating.
I need to get the body jacked up to see if there are any witness marks of spring eye contact with the chassis.

Pete · Post by **Pete** » Thu Nov 02, 06 8:38 pm

Quick Update:

Recently took the car for an MOT (passed!) and had a good look under the rear suspension.

The Pinion Snubber is already in contact with the floorpan - that probably explains the poor ride on the road

No witness marks near the shackles or springs on the chassis rails so it looks like I am not running out of travel there either.

The springs are already fairly well clamped up at the front.

I guess the next "fix" is new Slicks. I would like taller ones if there is enough clearance.....

Any other ideas or improvement suggestions guys and gals?

Ian Z · Post by **Ian Z** » Thu Nov 02, 06 10:25 pm

After my own first 'personal' shake down runs this year, this is an interesting thread. Inexperience is prob the biggest issue for me, but traction off the line is a real killer, so keen to hear others experiences and resolutions.

Pete · Post by **Pete** » Thu Nov 02, 06 11:07 pm

Hi Guys, for reference, this is the car at rest.
At the track I lower the suspension 3 turns on the torsion bars. Slicks are the same height as the road tyres....

Kev · Post by **Kev** » Fri Nov 03, 06 12:29 am

I know my 318 ain't making your HP but this is the set up, and it works (both wheels up); 3 1/2 Fentons running 165/70x15s, /6 torsion bars, 90/10 shocks, 8.5x15 Sluts wearing 28-10.5" slicks@12psi, 50/50 shocks, home brewed SS springs, clamped on the front leaves, wind up pinion snubber that wouldn't reach to 1/2" off the floor with my last run weight saving! It was about 1-1 1/2" from the floor. The slicks still wrinkled on launch. I'd say get some new meats under the rear, and see how that fairs. Xmas is coming, Julie is accommodating, Sorted!

Pete · Post by **Pete** » Fri Nov 03, 06 8:31 am

Cheers Kev; I would say our set up is fairly similar; but given who was the "inspiriation" then that is not a great surprise.

I guess now the winter is more or less here it is back to bench racing and research in readiness for next season