What Manifold/exhaust System On 1.6

[RobMGti 0]

madaxgt

 

It could be usefull to some members to say where you managed to get obtain the split Arvin downpipe from as i know a few members have struggled to get the originals of late.

 

Rob

[GLPoomobile 958]

www.buypartsby.co.uk do them. Shouldn't be a problem getting one, it's just that Matt had issues with postage costs when he tried to get one.

[pug_ham 240 3 Cars]

More to the point we were expecting a slight increase in performance compared to the bosal system (no split in d/pipe) we took off but noticed none it even seems slightly less. We even went to the bother of measuring it for a laugh starting from 1500revs in 3rd at a set point on a road up to 6k revs and the times were virtually identical with the new system being a few tenths slower. Not precise I know but overall performance seems no better and I thought 3rd gear would be long enough to show any improvements in the power/torque curve even by stopwatch standards. Also puma racing and others mention huge chunks of missing torque/power by having no split and I have seen no real difference on this well running/maintained car.

I don't know about missing huges chunks of power but it could cost a few lbft & bhp by not having the split but you wouldn't notice any difference in performance for any change of less than 10bhp/lbft anyway imo whatever system you have fitted.

 

In a well looked after car where everything else is spot on as Peugeot intended on the most difference you'd notice would be measured in tenths of a second anyway & wouldn't be felt behind the wheel.

 

Graham.

[hengti 2]

I don't know about missing huges chunks of power but it could cost a few lbft & bhp by not having the split but you wouldn't notice any difference in performance for any change of less than 10bhp/lbft anyway imo whatever system you have fitted.

 

In a well looked after car where everything else is spot on as Peugeot intended on the most difference you'd notice would be measured in tenths of a second anyway & wouldn't be felt behind the wheel.

 

Graham.

 

 

I dunno

 

The benefit of the magnex manifold is in an increase in torque - it won't be big numbers (mebbe 5ish ib/ft) - but you can definately feel it

[veloce200 3]

I reckon that after the sleeve type fittings they went to a baffled rear box. Being an owner of a Phase one (gotta love the hi-quality plastic on the dashboard - oh and I prefer my indicators orange thankyou !!!) I can say that on track it was always a lot noisier than other std Phase 2 205s when I ran it in std prod sprints. Straight through boxes always get a lot noisier with age too. Maybe the only thing we can glean for sure is the best aftermarket replacement for a mildly tuned 205 is the phase one system?!

 

When he replaces it maybe I'll get Mattsav to flow test Phase 1 and 2 backboxes on his flowbench.

[veloce200 3]

I reckon also the 4-2-1 manifolds have primaries that are too long. The GTI has a fairly "high" state of tune as std and longer primaries will tune it for more bottom end torque but at the expense perhaps of torque higher up the rev range. As midrange torque isn't an issue on any 8v engine they are a bit pointless. I think what us 8valvers need is a 4-1 manifold designed for firebreathing motors. This is where the gap in the market is. Trouble is 4-1 is more sensitive to pipe lengths and with a big cam even more so, and how many people on this forum are going to run 300 deg cams and 12:1 on the road?

 

As for bad aftermarket systems DVizard on Aseries (I only wish we had a bible like this for the XU - care to write one Mr Baker? ) tested a PECO exhaust - big bore - twin pipes that flowed 80.4 cfm!! As a comparison the std Mini one flowed 85cfm and the RC40 (not a big bore - smaller pipes than Peco but just well designed) flowed 195 cfm. Also we can't assume offset pipes are bad - the Sonic Turbo he tested has offset pipes and flowed 330cfm.

[pug_ham 240 3 Cars]

I dunno

 

The benefit of the magnex manifold is in an increase in torque - it won't be big numbers (mebbe 5ish ib/ft) - but you can definately feel it

Maybe but I guess your car had a full Magnex system fitted & was tuned for it rather than just swapping for one make of standard system to another without any other adjustment or tuning.

 

Also the noise makes it feel faster, general opinion in tuning circles afaik is that you'd be really hard pushed to genuinely notice a difference driving a car with much less than a 10lbft increase & tuned appropriately.

 

Graham.

[Rippthrough 98]

Maybe but I guess your car had a full Magnex system fitted & was tuned for it rather than just swapping for one make of standard system to another without any other adjustment or tuning.

 

Also the noise makes it feel faster, general opinion in tuning circles afaik is that you'd be really hard pushed to genuinely notice a difference driving a car with much less than a 10lbft increase & tuned appropriately.

 

Graham.

 

 

Hmm, it's more like a percentage difference than an absolute. If for example your car was fitted with the 1.1 TU engine you would most certainly feel a 10bhp boost!

 

On a 500bhp Skyline you wouldn't even know.

Edited February 7, 2006 by Rippthrough

[hengti 2]

Hmm, it's more like a percentage difference than an absolute. If for example your car was fitted with the 1.1 TU engine you would most certainly feel a 10bhp boost!

 

On a 500bhp Skyline you wouldn't even know.

 

That's my line of thinking too

 

The std 1.9s got about 120lbft - you'd notice a 10% increase! You'd prolly notice a 10% increase in most cars - it's a ... 10% increase ... !

 

Car was tuned - although I realise that some people do spend hundreds of pounds on kit and don't then bother with the RR tune which actually gives them the benefit of fitting all that stuff! Never understood why some people miss out this vital stage myself

[pug_ham 240 3 Cars]

Hmm, it's more like a percentage difference than an absolute. If for example your car was fitted with the 1.1 TU engine you would most certainly feel a 10bhp boost!

 

On a 500bhp Skyline you wouldn't even know.

That's my line of thinking too

 

The std 1.9s got about 120lbft - you'd notice a 10% increase! You'd prolly notice a 10% increase in most cars - it's a ... 10% increase ... !

I also agree but a 10bhp boost on a 1.0l engine is more like a 25% increase in power & an exhaust alone will never give that kind of increase on a non turbo car with that sized engine.

 

If you note I said anything under 10lbft is generally un-noticable (iirc they said 7bhp in the article I read), but also my personal opinion as something which strikes true.

Car was tuned - although I realise that some people do spend hundreds of pounds on kit and don't then bother with the RR tune which actually gives them the benefit of fitting all that stuff! Never understood why some people miss out this vital stage myself.

Something which has always baffled me also, why spend money on loads of bits & then not have the car set up to suit whats been changed. Admittedly you need a decent rolling road to do this & they tend to be few & far between where 205's are concerned.

 

Graham.

[Rippthrough 98]

I also agree but a 10bhp boost on a 1.0l engine is more like a 25% increase in power & an exhaust alone will never give that kind of increase on a non turbo car with that sized engine.

 

If you note I said anything under 10lbft is generally un-noticable (iirc they said 7bhp in the article I read), but also my personal opinion as something which strikes true.Something which has always baffled me also, why spend money on loads of bits & then not have the car set up to suit whats been changed. Admittedly you need a decent rolling road to do this & they tend to be few & far between where 205's are concerned.

 

Graham.

 

I guessed that's what you meant. I'd reckon you need about 5-7% for a change to be noticable, anything else would be placebo effect.

[Pug_sport 0]

My 1.9 was running with a powerflow exhaust and after reading pumaracing website I decided to try a standard one. After putting the standar one back on I found it to be more responsive it revs quicker you don't end up deaf on dual carriage ways and it pulls upto the red line which it didn't with the powerflow.

Stick with the standard exhaust it is an exellent system and as for 15hp increase it might be if the engine was knackered they have then fitted the exhaust and possibley done a rolling road set up which hasn't given them a 15hp increase it has just sorted out the problems which they could have done keeping the standard exhaust.