Thinking of going sequential, some questions first!

Thinking of going sequential, some questions first!

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Ross_328i_sport

Original Poster:

312 posts

209 months

Monday 18th August 2014
quotequote all
Further to my previous thread regarding the engine rebuild hours of the duratec engine in various levels of tune I am also now thinking along the lines of incorporating further upgrades to the car whilst the engine is out and this relates to the gearbox and replacing the current Caterham 6 speed with a sequential.
Basically I have 2 options in terms of engine spec that I need to choose between: -

Relatively Standard 220 BHP
Forged internals and 260 BHP

My questions are what needs to be done to fit a sequential gearbox and are there any optional items worth upgrading whilst doing the change and does this change depending on the power levels you run.

My car is an 2003 SV (Engine has been changed from K Series)

It would be nice to hear from anybody that has done the change or has nearly finished their research. Some of the questions I have: -

- Has there been any chassis modifications strengthening been needed (i.e. tunnel widening or extra diff supports) I do have the diff support from Caterham fitted to the car.
- ECU and GCU wise I am fairly aware of in terms of what is required.
- Does the prop-shaft diameter need to be increased and stronger material selected?
- Is it worth changing to an ultralight flywheel and clutch combination? How long do these last and what are recommended?
These are the issues/ problem areas I can think of at the moment however if there are more areas where installations have become difficult or with hindsight you would have done it a different way then please your experience is appreciated.

Thanks
Ross

DCL

1,215 posts

178 months

Monday 18th August 2014
quotequote all
As you probably know, I'm in the process of doing this and plan to do the gearbox swap this coming week. What I've learnt so far is that the more you can reduce the mass of the engine the better. Solid plate(s) clutch and uprated prop are required for durability and this means spreading the chassis members in the rear of the tunnel. Diff supports are also recomended. Flat shifts are really dependant on ECU but Geartronics do a well proven solution's too.

I plan lto blog the swap so will update progress and problems as I go.

Edit: just to add that my car is a metric s3 and I'm not sure about prop clearance on the sv chassis.

Edited by DCL on Monday 18th August 21:59

Ross_328i_sport

Original Poster:

312 posts

209 months

Tuesday 19th August 2014
quotequote all
Thanks for the information.

Reading through the thread you posted and the research you have done how long are you expecting out of the clutch and what clutch and flywheel combination are you using?

Moving forward with my car I have decided I will only complete track day in the car and race the fun cup therefore on the engine side of thinks am looking at going for a relatively standard engine for reliability therefore would appreciated what those who race in the R300 series have done to achieve reliable running out of their change to sequential and what clutch and flywheel combination they are using.

k20erham

372 posts

125 months

Tuesday 19th August 2014
quotequote all
Hi there, I put the Sadev with overdrive 6th on the back of my K20 Honda, replacing the Caterham 6 Speed at the same time fitted Geartonics SC Ecu to Gcu no problems, seamless shifts up and down. SWR do any mods for your clutch push bearing spacing and boxes are in stock. I run a 3.14 diff with HD tubed prop. SWR family run firm and very very helpful.

fergus

6,430 posts

274 months

Tuesday 19th August 2014
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k20erham said:
SWR family run firm and very very helpful.
+1

IBDAET

1,655 posts

262 months

Tuesday 19th August 2014
quotequote all
Clutch life for 5.5" twin plate sintered approx 1500miles.

You should upgrade the prop to protect your legs, not just to improve reliability.

Advisable to also weld some hoops in the chassis to save you legs/thighs should the prop nose or tailhousing of gearbox fail (all Type 9 prop noses are cast in Turkey, so its not unusual to get one which is flawed. I've seen them unpeel and do huge damage.)




DCL

1,215 posts

178 months

Tuesday 19th August 2014
quotequote all
Ross_328i_sport said:
Thanks for the information.

Reading through the thread you posted and the research you have done how long are you expecting out of the clutch and what clutch and flywheel combination are you using?

Moving forward with my car I have decided I will only complete track day in the car and race the fun cup therefore on the engine side of thinks am looking at going for a relatively standard engine for reliability therefore would appreciated what those who race in the R300 series have done to achieve reliable running out of their change to sequential and what clutch and flywheel combination they are using.
I'm using 7.25 inch twin plate sintered clutch and lightend flywheel. I've run about 500 miles on it and will check its condition but would hope to get about 2000 miles.

In terms of reliability, I think up to 270 bhp they are much the same - it is really about the rpm you wish to run more than anything else, but a well spec'd engine will have a lower inertia which is better for clutchless changes.

+1 for SWR, but my order took over six weeks.

Edited by DCL on Tuesday 19th August 17:57

Ross_328i_sport

Original Poster:

312 posts

209 months

Wednesday 20th August 2014
quotequote all
From the perspective of using a relatively standard engine how many miles would you expect to see from a 7.25" clutch utilising a sequential box?

DCL

1,215 posts

178 months

Wednesday 20th August 2014
quotequote all
This is an area where a conversation with SBD might help. My understanding is the wear rate is down to the sintered friction material. It is needed to cope with the heat generated by race environments. You could fit an organic solid plate that would be easier to drive and last longer, but it would not deal with racing starts, or big power, so well.

http://www.sbdev.co.uk/Gearbox/Super%20Clutch/Supe...

I would work out what you want from the car and not make the mistake to assume the race item is better. Often they are about solving problems, cause by extreme use, rather than increasing the service life.


Edited by DCL on Wednesday 20th August 20:03

DCL

1,215 posts

178 months

Wednesday 20th August 2014
quotequote all
This is an area where a conversation with SBD might help. My understanding is the wear rate is down to the sintered friction material. It is needed to cope with the heat generated by race environments. You could fit an organic solid plate that would be easier to drive and last longer, but it would not deal with racing starts, or big power, so well.

http://www.sbdev.co.uk/Gearbox/Super%20Clutch/Supe...

I would work out what you want from the car and not make the mistake to assume the race item is better. Often they are about solving problems, cause by extreme use, rather than increasing the service life.


Edited by DCL on Wednesday 20th August 20:09

IBDAET

1,655 posts

262 months

Wednesday 20th August 2014
quotequote all
Organic will be fine. Sintered actually wears the intermediate plates, not the friction plates. 7 1/2" is too big though. Take it from me I ran a Seq box and put up with all the damage it did to my car for 7 years.

k20erham

372 posts

125 months

Thursday 21st August 2014
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Hi, I,ve run a normal sized Greedy flywheel and pressure plate with a AP paddle plate Sadev overdrive box and Geartronics for nearly 3 years, 180 ft lb 9500 rpm 3500 miles track and London traffic with no issues