R400 K and R400 Duratec performance and handling

R400 K and R400 Duratec performance and handling

Author
Discussion

SpeedYellow

Original Poster:

2,533 posts

232 months

Wednesday 10th March 2010
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So ignoring the reliability merits of the two engines, anyone with experience of the two could shed some light on handling and performance differences between the two, would be very grateful.

Cheers

Supertoadylight

278 posts

201 months

Thursday 11th March 2010
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v. basic as im not sure of specifics but the duratec has more torque and you won't have to rev it as much to get the performance out of it. The k-series LOVES to be revved.

The k series is quite a bit lighter than the duratec - so overall performance is probably almost identical. (considering duratec has more torque). However the K-series in a straight line might have the edge (would be interesting to find out!)

On a track - a duratec will be alot easier to abide by noise regulations.

The k-series does sound a hell of a lot better though.....

Positives and Negatives for both. I know you said "aside from reliability"... so you already know which decision should be made financially....!

Stickshifter

174 posts

212 months

Thursday 11th March 2010
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As is says above...I have had both and currently have the Duratec. Chassis had some updates too for the Duratec. "Out of the box" noice reg so much easier to hit, I struggled with my K series partly due to need for re-packing. Just a refinement/advancement on the K series both great will equal amounts of fun.

-S

Stickshifter

174 posts

212 months

Thursday 11th March 2010
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Just to add...just pulled the R400 out of its carccon for Winter (been in there since October)....deflated tires, checked levels.....jumped in started first time and went for a blat...perfect.

-S

SpeedYellow

Original Poster:

2,533 posts

232 months

Thursday 11th March 2010
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Thanks for the answers, have decided to go for a K R400 as found the spec I was after for a good price and couldn't justify the extra £8k for a Duratec version for the mileage it's going to do over the next couple of years. The one I'm buying has a fresh engine so fingers crossed should be good as gold for a while.

fatvik

354 posts

188 months

Thursday 11th March 2010
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Pics man! P I C s!
biggrin

Enjoy
-FatVik

SpeedYellow

Original Poster:

2,533 posts

232 months

Thursday 11th March 2010
quotequote all
Next week when I collect it I'll be posting lots of pics...just going to have to keep you waiting

Dave J

891 posts

271 months

Friday 12th March 2010
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I have owned both engines with very similar power levels within the same chassis and setup. The duratec is 12Kg heavier than the k series was as a complete setup in my car. This will vary depending on each engines spec so a broad staement " the duratec is a lot heavier" is simply inaacurate.

The duratec is a little quieter on induction but the exhaust is the same. The turin response with the duratec is ever so slightly less with the duratec vs K series but the torque out of the corners is benificial. Straightline speed depends entireley on power of each engine. But the slightly lower reving nature of the duratec can have an effect on lap times if it clashes with your gearing and gears out of key corners on track. The duratec has a more linear power delivery whereas the K series would come on cam at 5500 and spin up the rear wheels and disrupt the car out of corners - especially in the wet. The duratec is easier to drive in this respect.

For road use the duratec is better - more torque and easier to keep on the boil.

my conclusion would be that the K series is better at power below 200bhp, above 200 bhp I would plump for a duratec.

dj

James.S

585 posts

217 months

Friday 12th March 2010
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Have had a K series R400 and currently race a Duratec R300. The race car is significnatly modified over the road car and is more comaprable to the D400 roadcar in powerlevels so comparision is not to far fetched.

The cars are different, however the Duractec in a metric chassis is better in all areas than its predecessor, period.




casbar

1,112 posts

220 months

Friday 12th March 2010
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James.S said:
Have had a K series R400 and currently race a Duratec R300. The race car is significnatly modified over the road car and is more comaprable to the D400 roadcar in powerlevels so comparision is not to far fetched.

The cars are different, however the Duractec in a metric chassis is better in all areas than its predecessor, period.
Interesting, what advantages does the metric chassis have over the Arch one then? Haven't heard anyone express that view before.

James.S

585 posts

217 months

Friday 12th March 2010
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Metric chassis is quite a bit stiffer, however they don't tend to bend back aswell as older ones.

You could see it in RSA class where K series engines feature in both chassis, metrics are a little more successful at putting power down in certain instances.


casbar

1,112 posts

220 months

Friday 12th March 2010
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Well you learn something new every day! I had always assumed that the Arch chassis was the better bet, and the metric was not as good (only from reading blatchat etc).

ge2

298 posts

254 months

Friday 12th March 2010
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Out of (vested) interest, is the R300 race chassis much different from the road version you'd get with a Duratec starter kit?

fergus

6,430 posts

280 months

Friday 12th March 2010
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casbar said:
Well you learn something new every day! I had always assumed that the Arch chassis was the better bet, and the metric was not as good (only from reading blatchat etc).
When Phil Squance @ Caged was making the new metric chassis, before caterham f*** ed him over, he showed me on their FEA package how the addition of a couple of tubes and the slight change in a couple of the triangulation points led to a large increase in both torsional and lateral rigidity. Arch can retro mod most chassis to achieve similar levels of stiffness. W/o a cage, the std chassis isn't great torsionally along the length of the car, and also has poor resistance to a bending moment around the bulkhead. A cage will solve a lot of the stiffness problems. Good dampers can also help a lot.

casbar

1,112 posts

220 months

Friday 12th March 2010
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Met Phil when he fitted my full cage, nice bloke, and the cage has made a lot of difference to the chassis, I also run Nitrons, so guess I don't need a metric chassis just yet smile

Edited by casbar on Monday 15th March 17:03

RobM77

35,349 posts

239 months

Monday 15th March 2010
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Regarding the old vs the new metric chassis, I thought the metric chassis was announced from day one by Caterham as being stiffer, as James says?

casbar

1,112 posts

220 months

Monday 15th March 2010
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There seemed to be loads of posts about the two chassis, I seem to remember Arch and Caged, were doing a different kind of welding (don't quote me on that though).

They both seem to be ok, I haven't had any complaints, although as I said in an earlier post, the cage does make a huge difference to the Arch chassis smile

fergus

6,430 posts

280 months

Monday 15th March 2010
quotequote all
casbar said:
There seemed to be loads of posts about the two chassis, I seem to remember Arch and Caged, were doing a different kind of welding (don't quote me on that though).

They both seem to be ok, I haven't had any complaints, although as I said in an earlier post, the cage does make a huge difference to the Arch chassis smile
Caged used robot MIG, and Arch used Bronze welding. The FEA package Caged had was sufficiently robust to not only show all the stress points as a result of any custom point of deflection, but also the results alone were sufficient to offer to the FIA for cage certification, w/o needing to pop the Cage up to MIRA for evaluation.

Unless Caterham have similar levels of technology available to them, it may just be the opinion of an experienced fabricator which suggests chassis A is 'stiffer' (poor engineering term) than chassis B?