R500 Cadwell peak speeds - down on power?

[Walton]

My car felt underpowered yesterday at Cadwell, despite the engine running smoothly. My mate's E92 M3 had the legs down both straights, and the other R500 in attendance could easily gain on me, despite me running the foam airbox (he had the restrictive carbon box), albeit I had a windscreen and he had the aero.

Acceleration felt like a crawl once over 100. Was seeing peak speeds of 110mph (GPS accurate) on both straights, and was taking Coppice flat so no early braking.

Can anyone let me know what speeds they achieve on the straights - surely it should be 125+?

Cheers

Rich

[JeffC]

I would expect the windscreen to kill top end power over aeroscreen but an R500 should have enough grunt to pull top end? I know My csr 260 road car will get close to the rev limiter in 6th which is indiacating well over 150 and pulls pretty strong all the way ??..

I would expect an R500 to be going more than 110 down the straight at cadwell quite sure my pals Honda civic 1.6 race car is doing that Im goind back a few years now but im pretty sure in my last Caterham track car was seeing over 125 and I definatley couldnt/didnt take the corner at end of pit straight flat on kumho tyres?
did u take a note of lap times ?

[JeffC]

yep just watched an old trackday video from a few years ago and even getting slowed down coming out of Barn in 2nd I change up into 5th going over the start line and my car did 120 in 4th and It travelled a fair way in 5th before i backed off for Coppice. my car had more power than an R500 but would still expect R500 to be close.?

also noticed on your other thread you said Gooseneck was close to flat out on slicks??? again pretty sure you should be entering that close 120mph on slicks??

something doesnt sound correct if you were only seeing 110 ?

Edited by JeffC on Thursday 9th September 16:38

[pw75]

worth checking the throttle position sensor if its similar to the ones on the 300d race cars. Similiar ish sounding symptoms, down on power esp at top end. I was loosing 10mph down hanger back before easter. How you check it without a computer and the right cables though I don't know.

[Walton]

Thanks.

The more I think about it, the more I realise something was definitely wrong. In 5th and above there was not even enough drive to overcome drag and there was no acceleration at all.

Was managing 135mph at Bedford the other week and that was with Carbon box and windscreen - I imagine another 5-10mph would be possible with aero. Very impressive considering my old 300 Atom only managed 140mph.

[ArosaMike]

Worth checking the Cat if it's fitted as well. They have a habit of collapsing at the moment!

[thequietone]

Worth getting the wiring on the map sensor checking out - there is a few issues with those at the moment. Had mine break and caused loss of power and poor running at high rpm. Simple fix though and now back on song.

Not done Cadwell in the '500 but was seeing north of 120mph in the R400 before Coppice.

[Nicodema]

Rich, I have the MBE ECU adapter if you want to pop over and see if there's anything messed up. Coincidentally I used it at lunchtime to finally find out that my throttle pos sensor wire had fallen off.

I'll be fixing that over the weekend, hopefully with a R300 race subloom from CC Dartford. We're popping down there tomorrow to drop the old diff off and pick up a set of 13"s and ZZRs. I'm keen to find out how good they are.

Martyn

[FunkySon]

Nicodema said:

We're popping down there tomorrow to drop the old diff off and pick up a set of 13"s and ZZRs. I'm keen to find out how good they are.

Martyn

I didn't think CC at Dartford was open on a Saturday morning any more.

Might be wrong though.

[Nicodema]

You are technically correct, the parts dept is closed. There is generally a small contingent of workshop staff who can be prevail upon to do Checkpoint Charlie style exchanges when necessary.

[Walton]

Cheers for the suggestions.

It may be the cat as the car's been back-firing and cracking an awful lot.

[edb49]

Walton said:

Was managing 135mph at Bedford the other week and that was with Carbon box and windscreen - I imagine another 5-10mph would be possible with aero. Very impressive considering my old 300 Atom only managed 140mph.

How did you manage to do Bedford in the R500 and not get thrown off for noise? I like the circuit and have got an R500 so keen to see any workarounds..

[Walton]

I've done Bedford a couple of times over the last month. Both times with trackday silencer and carbon airbox.

1st time I had a static of 93db, but the lower tab of my airbox was broken and didn't fit correctly, so I got black flagged for coming very close to the drive-by limit - marshal told me where the sensors were and I just gave them maximum clearance and eased off.

2nd time - my exhaust was losing it's packing and I registered 120db static. After being allowed to test at 3500rpm I just squeezed under 100db. Again just took it very easy near the drive-by sensors.

I've seen a few other R500Ds at Bedford without probs.

[edb49]

Do you have the straight cut sequential box too? Perceptively that contributes quite a bit to the drive-by noise, although I'm not sure if that's because it is a louder or more 'interesting' noise than exhaust etc.

[Walton]

Nope - standard 6-speed, though I have seen people driving there with the seq box without any probs.

[FlyInMySoup]

Touching 120mph, 1600 K series with aeroscreen.

[Walton]

Cheers. Now fixed. Was a mis-adjusted throttle switch near the airbox. Was only running at 3/4 throttle!