2+2 exhaust single to double pipe

[beachbugy]

Hi i have a s2 2+2 i have read recently the lack of power is in some ways due to it having a 2 to 1 then back to 2 pipe exhaust system, obviously restrictive ! i also read the standard exhaust nocks 10% of the performance off. my question is can i use standard front pipes from another model and make it a 2 pipe system ? and is there a reasonably priced better exhaust that give more umph!! not worried about noise im an old boy racer

[Heuer]

You should have a four branch manifold joining two down pipes to two silencers and two resonators. If not you can fit the system designed for an S1 2+2. Speak to these guys: http://www.classicfabs.co.uk/ as the resonator tail pipes on your car will be a different shape.

[beachbugy]

i have 2 3 branch manifolds 2 down pipes into 1 then back into 2 middle pipes, i take it from the reply the s1 2+2 has a 2 pipe system, the sc parts book shows it having a single pipe system, is the extra length in the middle pipes ? or the front pipe

[beachbugy]

iv check the parts numbers the series 1 and 2 2+2 are the same at the front pipe ?

[Heuer]

Never realised the 'standard' 2+2 system siamese'd the pipes!


As I said however you should speak to ClassicFabs, Hayward & Scott, Bell or one of the other manufacturers and get them to supply you with a system of the correct length for the S2 2+2 with individual pipes all the way. Should give you a nice boost in power. If you are going to use ClassicFabs you will need to decide on whether you want a full system including manifolds or just the partial system without. They do two bore sizes and offer a choice of venturi's to adjust the noise level.

[PETE V]

you learn something new every day

P.V.

[beachbugy]

thanks for the classic fabs thing not being ungratefull but not looking to pay ?600 + pounds for pipes, i was looking more for fit normal front pipes of a 4.2 etc ? to remove the single pipe, the exhaust i have is new, i may just chance buying some front pipes and making them fit, just wondered if someone had solved this easily without rushing round to expensive pipe benders.

[Heuer]

The problem you will have is the 2+2 is longer than the standard car. The silencers are also different however SC Parts sell adapter pipes - SJ 3019/BB and SJ 3020/BB to allow you to get over the single pipe problem. Suggest you contact SC Parts to ensure the part numbers are correct before ordering.

[beachbugy]

thanks for the info top ! now thats sorted i have an admission i bought a 420g inlet manifold and carbs to make it 3 su`s instead of 2 ooops it wont fit without bonnet scoop ! double oops, my question is has anybody modified one to fit ? i have some ideas as how to cut and reweld it but is there an easier way ? without spending ?500 on a new manifold

[JEP41]

Back in the early 1980's I installed a MK10 manifold and triple SU setup on an XJ6 Coupe and ran into the same problems. I took the manifold to machine shop and had them mill the manifolf to cylinder head face at an angle to reduce the deflection upward. It ended up with the manifold flange thinner at the bottom side than the top, but as the weght loading is down this is not a problem. I ran the car for four years with no problems before it was sold on. :D

[beachbugy]

interesting idea i was thinking of putting a spacer plate inbetween say an inch thick but drilled upwards to lower the manifold, how much lower do i need to make it so i get clearance is my issue ? i will keep an eye out for a second hand manifold but they are rather rare

[christopher storey]

If you put a spacer in you will need to be very careful that you do not run into the problem of the base of the carbs chattering against the frame rails

[PeterCrespin]

thanks for the info top ! now thats sorted i have an admission i bought a 420g inlet manifold and carbs to make it 3 su`s instead of 2 ooops it wont fit without bonnet scoop ! double oops, my question is has anybody modified one to fit ? i have some ideas as how to cut and reweld it but is there an easier way ? without spending ?500 on a new manifold

First point: If you are going to the trouble of modifying your 2+2 downpipes to get more power - fuggedaboudit. There's no difference you can measure and Jag certainly never listed any change. If your car is an auto you need the siamese to clear the auotbox sump pan. If it's a manual you'll be OK but will waste your time and money if you want more power. Siamese exhausts usually help torque slightly and the single pipe on the 2+2 is bigger bore than the fore and aft twin-pipe sections. The geometry of cross-sectional areas and related fluid flows/boundary layer effects means the single pipe is not really any impediment.

For the SUs, your idea of a 1" spacer will screw up the air cleaner connection by bringing the carbs too far outboard. Even if you aren't going to run a stock air cleaner you'll also screw up the bulkhead to manifold alignment and this will interfere with your linkage. Then you'll still have the manual choke to sort out, unless you stick with the electric choke/starting carb. In fact, as per the exhaust, if you are going to all this trouble to find more power then you won't notice much until/unless you floor it, because 2 x 2" SUs flow plenty of air at all but wide-open throttle and high revs. Do you *really* drive like that? I guess at least the triple SUs are pretty, unlike the invisible 'de-siamese' project.

Your carbs are higher than normal so machining an angle on the inlet side will drop them lower. Provided you don't drop them lower than stock they'll clear the frame rails OK. You ought to machine an opposite taper along the carb faces of the manifold to bring them back to horizontal, which will help. You're either going to have to draw it all out carefully or do the geometry with correct dimensions if you want to avoid lots of trial and error machining. Think twice, cut once as they say...

If you want to prettify your car then use S1 resonators, dump the stainless rear trim panel and clam shells and use a long narrow number plate. Replace the tacky MG reversing lights for Lotus rear light clusters with the reversing lights built in. Looks far tidier and less tail-heavy than the normal S2 (works for the S3 too).

Pete
[/img]

[mgcjag]

Hi Peter.......Interested in you Rear light info but never seen the Lotus light conversion (do you have a photo?) also what are Clam shells? thanks Steve

[beachbugy]

firstly it a manual car, i think it barretts that quote the single pipe as a restriction, its not the pipe diameter which is the issue though its the exhaust pulses all meeting at too closer a point to the engine causing a back pressure wave, im going to buy the sc parts conversion pipes, your right about its bum though ugly i have s1 tail pipes ready to go on, interestingly though mine never had a finisher strip across the back, i also have to dissagree with you about the carbs 2 strombergs to 3 su`s puts about 30bhp into the engine, and yes i do intend to give it some welly, i have been thinking about the manifold, like you say machine an angle at both ends would do it quite nicely if i put cone filters on sort the filter issues, im wondering if the angle of the manifold would have much effect, maybe i should just save up for a proper one

[Heuer]

Hi Peter.......Interested in you Rear light info but never seen the Lotus light conversion (do you have a photo?) also what are Clam shells? thanks Steve

Steve

The Lotus Elan used parts from various production cars (the front indicators and sidelights are off an Aston Martin DB5, for example) and the rear light cluster's were from the S2 E-Type parts bin, used up side down.



Lotus modified them slightly to include the reversing lights so using a pair allows you to tidy up the rear of the S2 by dumping the separate ones. This allows a rectangular number plate to be fitted and S1 resonators. The 'clam shells' are the chrome finishers which wrap around the light clusters which you can also leave off along with the stainless flat panel.

[PeterCrespin]

Hi Peter.......Interested in you Rear light info but never seen the Lotus light conversion (do you have a photo?) also what are Clam shells? thanks Steve

Clam shells are the chrome finishers on each side blending the lamp cluster to the body. They aren't a bad item but they stick out and make the back end look wider by drawing some attention to the lamps.

Odd that we can't post pics here - you'll have to PM me.

The Lotus lamps are different and rather than being a raid on Jag's bin I think they were just a variation on a theme. The Jag is the raider if anything, because the Jag bases have provision for the reversing lights which is not drilled for the bulbholder and reflector, so it is a cheap imitation of the Lotus rather than vice versa IMHO. The lenses are the same except Lotus specified a clear insert in one of the slots where Jag asked for a reflector. Technically you could try putting a clear ribbed lens in there and knocking out some kind of bulb holder of your own design.

[/img]C:\Documents and Settings\Pete\My Documents\E-type resto\Body\DSC02397[/img]

[Heuer]

Pete

You can post pictures here by following these instructions: http://etypeuk.com/forum/viewtopic.php?t=1666 Your link was to a picture on your PC which is not a good idea hence we suggest using a free Photobucket account to host them.

So point Photobucket at C:\Documents and Settings\Pete\My Documents\E-type resto\Body\DSC02397 and it will upload the picture, save it and give you a working link to post here.

Regards

David

[PeterCrespin]

Yeah, definitely maybe :-)

Am used to another forum using this exact same software, where we just add images from wherever into the posts themselves. Nobody can get at my computer. I tried the link thing just in case, but it was never going to work I guess with the way it's set up here.

If anyone wants to PM me, fine. If not, I might do something ma?ana when I get a round tuit.

[Nick]

There must have been a US lighting requirement that forced Jaguar to go with the separate reversing lights. Surely they wouldn't have made another tailpipe variant and lived with the rather messy (IMHO) rear detailing if they could have avoided it by putting the reversing lights in the lamp clusters.

Nick L.