JPSC Forum

So who's going to work on thier car over christmas and what have you got planned.

If the bits turn up I'm changing brake master cylinder sizes now RD do a 1/2" bore so it'll be F0.5" and rear 0.625" instead of 0.625+0.7" Hopefully it'll give me a bit more feel in exchange for a bit more travel.

Also thinking of putting the softer spings back on the rear that I took off in summer. Always used to bottom out so I went 20lb heavier but the new (shorter) shocks should have sorted the bottoming anyway. It didn't feel as good with these when on the limit; Too tail happy especially in the wet. Thats what you get when you change too much at once I guess.When my uprights cracked, I changed them, plus the shocks, springs and poly-bushed at the same time.

Then I want to play about checking the bump steer (and other geometry) while I won't be interupted by pesky customers.

Surely your '' shorter '' shocks will produce greater bottoming out due to their shorter piston travel -- unless of course you uprated spring lbs at the same time .Obviously the springs themselves can become ' bound ' if soft enough plus pretensioned -- but shorter shocks/less piston travel plus either soft springs/shorter springs/more weight in car will more likely bottom .

In theory when designing suspension but not quite in this case, as longer shocks have a longer compressed length.

I bought the original shock lengths based on the recommendation from KitCarWorkshop when building the car. Once built, I then found that the fronts were too short and the rears too long. I basically had very little to play with regards possible ride height, where the fronts were almost fully extended (so almost no droop) and the rears 2/3rds to 3/4rs compressed so not much bump. Fully loaded it'd hit the bump stops hard. Ironically the ride height and rake happened to be about OK (if a bit low for the road).

When I had it stripped for the uprights I swapped to longer front (extended top eye) and slightly shorter rear. Although they have slightly less overall travel I now have 1/3 droop and 2/3bump front and rear at slightly higher ride height. I also increased the rear shocks from 160lb/inch to 180. I might try a bit lower and 50/50 bump/droop later.

Im not going to be playing over christmas as im going to pig out abit. An extra 5kg isnt going to make that much difference overall as its a small percentage increase

I have just got a DL1 off ebay so i'll probably be researching what the best sensors are to get for it. It looks like it'll plug straight into the Canems ECU im running. I'll now be able to monitor oil temp so i can see if i'll need the next upgrade which'll maybe be an oil cooler.
Not too keen on this as im supposed to be adding lightness. (im sure that some of you are saying "what about the 120kg driver" )

still on the list is alloy hubs and a rewire but they'll have to wait.

@Adi

sounds like your old shocks didnt have enough preload so were compressing too much under the vehicle load.
do shocks work like this ? anyone? im only thinking on how my mountain bike worked years ago.

I'll be having a go at seeing what my shocks are like in the new year once i can figure out a way of working out the unsprung mass of the front wheels and rear axle (I have corner weights). I was thinking of whipping the shocks out and using fishing type spring scales in their place to see what the forces are pulling the shocks apart. I will obviously have to have the car jacked up to let the wheels hang.

There must be some one out there that would be able to make a suspension to the cars exact weights.

Looks like this guy had the opposite problem

http://www.neileverett.madasafish.com/m ... ampers.htm

I noticed this when I jacked up the rear of the car, and the wheels only dropped (with respect to the body) by about 15mm before they lifted off the ground.

Interesting read and good to see that the ideas used are taken from other cars to get you in the correct ball park

I then dug out some info on ride frequencies of mid or rear engined sports cars

Maybe a Christmas tidy in the garage.

pigeondave wrote:Im not going to be playing over christmas as im going to pig out abit. An extra 5kg isnt going to make that much difference overall as its a small percentage increase

I have just got a DL1 off ebay so i'll probably be researching what the best sensors are to get for it. It looks like it'll plug straight into the Canems ECU im running. I'll now be able to monitor oil temp so i can see if i'll need the next upgrade which'll maybe be an oil cooler.
Not too keen on this as im supposed to be adding lightness. (im sure that some of you are saying "what about the 120kg driver" )

still on the list is alloy hubs and a rewire but they'll have to wait.

The DL1 will not plug straight into the Canems, you will need a lead from Race Technology.

http://www.race-technology.com/wiki/ind ... /CanemsECU

Have a look here about how to set-up sensors...

http://westfield-world.com/rtdash2.html

While you don't have the dash the sensor setup is the same.

jeffw wrote:The DL1 will not plug straight into the Canems, you will need a lead from Race Technology.

http://www.race-technology.com/wiki/ind ... /CanemsECU

Have a look here about how to set-up sensors...

http://westfield-world.com/rtdash2.html

While you don't have the dash the sensor setup is the same.

I sort of knew i needed a double female thing (oo-er, who doesn't?)

thanks for the other link will have a read through later.

I'm going to get as many days as I can on finishing the wiring on my J15. Managed two days over the weekend, should be nearly done by return to work on the 5th of January.

pigeondave wrote:

jeffw wrote:The DL1 will not plug straight into the Canems, you will need a lead from Race Technology.

http://www.race-technology.com/wiki/ind ... /CanemsECU

Have a look here about how to set-up sensors...

http://westfield-world.com/rtdash2.html

While you don't have the dash the sensor setup is the same.

I sort of knew i needed a double female thing (oo-er, who doesn't?)

thanks for the other link will have a read through later.

You need a ECU cable, otherwise it will not work. £150 +VAT from the Race Technology Website.