Aeroscreen/R500

Author
Discussion

edb49

Original Poster:

1,652 posts

210 months

Friday 23rd July 2010
quotequote all
Has anyone had experience of a Duratec R500 with and without an aero screen?

Did a Silverstone track day on Monday and was a bit frustrated by top speed or lack of. At the end of the Hangar Straight I was getting to 127-129mph pretty consistently. (The speedo doesn't overread, so that is an accurate speed.)

I'm guessing with a helmet on it doesn't make much difference whether you have an aero or full screen? Any before/after experience of how it affects speed on the straights?

CatMatt7

100 posts

212 months

Friday 23rd July 2010
quotequote all
What gearbox and diff ratio do you have? I have a k-series R500 and it has a top speed of 138mph as determined on a rolling road while having it properly mapped. This is achieved at 8,620rpm.

Are you running out of revs or power?

I have always had an aeroscreen on my car, but I have heard that an aero is worth c. 10mph top speed vs. a windscreen. Also an aero is much more fun. I never quite understood having a windscreen if you are primarily using it on track with a full face helmet on.

I normally achieve c. 130 on the longer straights when on track, but the car isn't really about top end and much more about how quickly it gets there. Sevens are not aerodynamic cars, so they are always compromised on top speed versus other types of cars. The payback being the sheer rate of acceleration and handling. I would be fairly happy with 128mph. Might be worthnhaving the car mapped (if not actually done already) to find out what it will actually do rather than the stated figures.

Good luck

Matt


edb49

Original Poster:

1,652 posts

210 months

Friday 23rd July 2010
quotequote all
It's running out of power, I don't get into 6th gear at any point on the circuit. I think the car is geared to 148mph in 6th on the limiter.

The problem is with the faster circuits, you're coming out of a corner pretty quickly and so there's not much extra speed to "add" on the following straight.

thequietone

170 posts

206 months

Friday 23rd July 2010
quotequote all
Do you have the carbon airbox fitted?

edb49

Original Poster:

1,652 posts

210 months

Friday 23rd July 2010
quotequote all
thequietone said:
Do you have the carbon airbox fitted?
Yep, I've got the "track day" airbox fitted.

thequietone

170 posts

206 months

Friday 23rd July 2010
quotequote all
If you get the chance, whip it off and fit the standard foam filter and see how you get on. Should make quite a difference at the top end particularly if it's a hot day. Just fit the airbox for sub 105db track days.

edb49

Original Poster:

1,652 posts

210 months

Friday 23rd July 2010
quotequote all
Interesting... I wasn't aware that the airbox affected power much. I don't suppose CC have any info in that regard?

thequietone

170 posts

206 months

Friday 23rd July 2010
quotequote all
As far as I know, the airbox is to reduce noise rather than help feed the engine. The standard filter will draw nice, cool air from outside the bonnet whereas the airbox takes hot air (via a single cone filter rather than the four trumpets) from the not-so-cool engine bay.
You'll have a much stronger delivery from 5500 onwards.

edb49

Original Poster:

1,652 posts

210 months

Friday 23rd July 2010
quotequote all
Makes sense in theory, but I'd be interested to hear anyone's experience before I put £100 down for a bit of foam...

https://www.caterhamparts.co.uk/product_info.php?p...

thequietone

170 posts

206 months

Friday 23rd July 2010
quotequote all
Having driven back-to-back the difference is significant - felt like at least 10 or 15 bhp. Cant be the only one to have done/thought this so would good to hear someone else's feedback. Noise would be an issue on quieter TD's but for 105 days and road use it's happy days, actually feels like the 263bhp it's supposed to have!!

The Wookie

14,031 posts

233 months

Friday 23rd July 2010
quotequote all
If it helps, in an C400 race car (229bhp) I was hitting 135 on the start/finish before hitting the brakes for Copse

edb49

Original Poster:

1,652 posts

210 months

Friday 23rd July 2010
quotequote all
thequietone said:
Having driven back-to-back the difference is significant - felt like at least 10 or 15 bhp. Cant be the only one to have done/thought this so would good to hear someone else's feedback. Noise would be an issue on quieter TD's but for 105 days and road use it's happy days, actually feels like the 263bhp it's supposed to have!!
Interesting. I assume the back to back was on a Duratec?

edb49

Original Poster:

1,652 posts

210 months

Friday 23rd July 2010
quotequote all
The Wookie said:
If it helps, in an C400 race car (229bhp) I was hitting 135 on the start/finish before hitting the brakes for Copse
I wasn't getting to anything like that, probably 120-125ish.

EFA

1,656 posts

268 months

Friday 23rd July 2010
quotequote all
thequietone said:
felt like at least 10 or 15 bhp.
How do you quantify that???

Aeroscreen makes a big difference, but I think the problem with the Duratec R500 is that it does not have the revs hence produces its power and torque lower down than the old K car. To get the theoretical speed without the revs. the Duratec car needs taller gearing, but it does not then have the multipled torque to overcome drag.



Edited by EFA on Friday 23 July 11:55

Dave J

891 posts

271 months

Friday 23rd July 2010
quotequote all
I would go road and track rolling road
to get the actual engine power on the duratec r500 verified with and without the airbox

dj

thequietone

170 posts

206 months

Friday 23rd July 2010
quotequote all
Yup R500-D. The car felt particularly 'strangled' in the upper rev range during the very hot weather so swapped the airbox for the standard filter - BIG difference and well worth the outlay - only use the airbox now for the odd TD. It only takes tick to swap over so it only goes on if it's a bit loud.

thequietone

170 posts

206 months

Friday 23rd July 2010
quotequote all
Peak R500 (Duratec) power is @8'600 - same as the K Series car. The extra 600 rpm on the early cars was basically over rev.



OK, OK, so on the Duratec it's 8'500. Sorry!

Edited by thequietone on Friday 23 July 12:26

edb49

Original Poster:

1,652 posts

210 months

Friday 23rd July 2010
quotequote all
Argh, these cars!

Spoke to Caterham and they said the foam filter made a big difference to the top end, 10-20bhp depending on conditions like under-bonnet temps etc.

I have now ordered one of these and a wind deflector, will be back at Silverstone on 23rd August so be interesting to see what difference it makes.

edb49

Original Poster:

1,652 posts

210 months

Friday 23rd July 2010
quotequote all
thequietone said:
OK, OK, so on the Duratec it's 8'500. Sorry!

Edited by thequietone on Friday 23 July 12:26
Actually... I think the limiter is 8600, not 8500 as the manual says..

thequietone

170 posts

206 months

Friday 23rd July 2010
quotequote all
I can't quantify the extra horsepower gain hence the term 'felt like'- I would be supprised if it was any less though. Like DaveJ says, the rollers are the only way to put figures to the feelings.

Probably is @8'600 but I dont think the Stack keeps up! Be interested to hear what difference you notice with the aeroscreen and filter.

Edited by thequietone on Friday 23 July 12:33