4 to 1 exhaust conversion

[Tony Martyr]

A new subject following on from the post modification thread

OK I'm going to throw out the CAT exhaust and fit a 4:1 system as advertised in Demon Tweeks. I suppose they charge the same as Caterham?

Question One is do you have to carve a bigger hole in the body panel to get the 4 tubes through.

Question 2 is what is the justification for the 4:2:1 unit advertised for the Superlight R which must also fi a K series?

Ohter than body work I assume it is a simple bolting task and one rolls up the Lambda sensor and tucks it somewhere out of sight.

[Paul Ranson]

Usually Caterham are cheaper (!)

 

Paul

[CHRIS CLARK]

Yes, the body work hole is larger! I saw one recentley that had had this mod done & the owner must have used 'straight' tin snips; awful!!!

Can't say what to do with the lambda sensor, 'cos I ain't got one. Would have thought it was not to difficult to get a suitable boss fixed in place though.

D T are not known as 'Demon Thieves for nothing!

[Mat Norris]

Just fitted a 4 into 1 this weekend, but to a xflow. I heard curved tipsnips were the tool to have but could not find any. So I used a 3mm drill but and carefully drilled aroung the profile of the hole I wanted. I then used a half round file to smooth and shape. Result - Great looking and sounding exhaust and hopefully more BHP!

 

 

[Mike Bees]

The 4-2-1 supposedly fills up a hole in the torque curve at around 4000rpm. From back-to-back tests I've seen on a modified 1.6K it does very little, maybe it works better on the 1.8. It may be that the primary/secondary diameters are too big, or simply that the secondaries are a bit short.

 

As others have said, it's cheaper to buy direct from Caterham than from DT.

 

Mike

[Peter Carmichael]

The Lambda sensor was originally on a removable plug from the engine loom. I believe the thread in the boss is the same as for a spark plug, if you are looking for some way of blanking the hole that you have in the 4-1 as well as you had in the Cat exhaust. You will then be able to run the car on LRP.

 

The 4-1 will be fabulous. The 4-2-1 will do nothing extra for you.

[Snapper]

I have a 1.6k series Roadsport thats about a year old and people keep saying it will be better with a 4-1 exhaust system instead of the standard one.

 

But no one can tell me what it will improve other than the sound of the car. One person said it would give me 1or2 extra BHP. If this is true £ 300-400 is a lot for no real improvement in performanace.

 

Can any one tell me what real benifits I will give me?

[Peter Carmichael]

The noise from a 4-1 with 5 inch silencer on a 1.6 Supersport is within the limits for Goodwood quiet days, so I wouldn't worry about noise.

 

The 4-1 has longer branches. 3 of them are 29 inch and 1 is significantly less (oops). Overall, this design gives a much more helpful effect throughout the rev range than the very short standard branching which joins together within the engine bay. The length of the primary pipes gives an exhaust resonance - the longer the pipe the lower the revs.

 

The 4-1 will give you a healthier power delivery throughout the rev range. Noticeably so.

[Snapper]

Thanks peter, but would you say its worth paying the £400 for on a standard 1.6k Roadsport

[Snapper]

O' and what should it do for the 0-60 mph timing if the book is correct in saying 6.2 sec's under the same conditions. Cheers Peter

[Red SLR]

Not really on the same subject, but on Men and Motors last night there were some custom street fighter bikes, and they had been testing out a new exhaust can which was air brushed with the design of your choice. The test can had lasted over 12 months with no sign of chips or blistering.... maybe that would be a better £300 on an exhaust?

 

Simon.

 

 

 

X777CAT

[Slipper man]

As far as the Lambda sensor is concerned, the SLR's etc have a mounting for it in No.4 exhaust downpipe.

[Rob Walker]

Caterham can supply a paper template for the enlargement of the hole in the side skin. The easiest way to enlarge the hole is to mask the edges with masking tape and remove the metal useing a carbide burr in an electric drill. Finish with emery cloth and remove masking tape. Snips will buckle the side skin.

[Rob Walker]

Almost forgot, I would recomend you consider fitting the six inch box with the 4:1 primaries. The five inch is marginal at some circuits and it costs the same as the six inch. Your ears will also benifit.

[Luke Beaumont]

Tony, if you're looking to sell your standard exhaust system, count me very interested.

 

Luke

[Tony Martyr]

Luke,

email me off list at spanner-monkey@classic.msn.com and I'll advise you when I do the replacement, maybe a couple of weeks away.

Tony Martyr

[WILL FLY]

What's the cost of a 4-1 manifold and 6 inch box from Caterham. DVA suggested Exhaust by Design for a custom long 4-1 manifold for about 350 quid, then I'd need a 6 inch box (pref without cat). Is there any benefit in this or should I just go for a Caterham 4-1 manifold.

 

Roy

[Mike Bees]

The Caterham one is pretty good - I'm still using it on my ~240bhp K-series, which I suspect is being slightly strangled by the 1.5in primaries. I don't think you need (or want) bigger diameter primaries until you're over 200bhp. I reckon you're looking at around 400quid for the Caterham system (the manifold and collector come to just over 400 if you buy them individually, according to the parts CD, but Demon Tweeks do the whole system including 5" silencer for 500 and they're always more than Caterham).

 

Mike

[Peter Carmichael]

Roy,

 

My manifold is by Exhaust By Design.

 

It is a good piece of work, but it was only necessary because of the dimensions I was after. The Caterham 4-1 exhaust is very effective even up to high power outputs. Although with your 1.8 (capacity makes a difference) and your intent to tune, a Caterham 4-2-1 may be advisable.

 

The exit from the engine bay is the tricky piece in the exhaust design. It has to clear the alternator, water rail and starter motor as well as the removable chassis rail. My Exhaust by Design manifold is too close for comfort to the chassis tube and to the starter motor - indeed I cannot fit the race starter motor because the #4 primary would interfere with it. The exhaust was designed and first fitted to my Supersport with an original k-series starter motor and different water rail.

 

The downstream arrangements on the Exhaust By Design manifold are superior. The collector is located using longitudinal bolts through welded-on tubes - you can leave a couple of nuts in the middle of this arrangement so you can drive the collector off the primaries come dismantling time. I was also building back to a non-standard exhaust can and I was keen to get a bit more ground clearance than I had enjoyed with the Caterham 4-1 matched to Arnie's carbon fibre can.

 

The Caterham exhaust cans are not repackable. I have heard of people cutting them open, repacking them and then rewelding.

[JKJ]

If anyone just wants to install a 4-1 exhaust system for a x-flow for appearance, then Redline can supply a Y-piece to connect the primaries to the Caterham side exhaust with no cutting of the bodywork. Looks and sound great.