Exhaust Manifolds & Systems

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samuri-240

Well-Known Forum User
Need to get an exhaust system sorted for my Z shortly, with all this exhaust talk going on at the moment not sure which way to go anymore. My engine is a short stroke 2.6 with reworked head, cam, triple 40 Dellorto's etc, I have just removed a Janspeed manifold & system, the plan was to fit a Nismo 1 3/4" manifold with a single box 2 1/2" system, but then a twin pipe system has been mentioned, which is the best way to go single or twin pipe system ? Also it has been said the 1 3/4" Nismo is not suited to a small engine :( my only other option at the moment is the smaller bore GDS that I have, any help will be much appreciated.
 
I'm no expert but my GDS works well and I'm in no hurry to buy or make a replacement, try it.
 
Rob Gaskin said:
I'm no expert but my GDS works well and I'm in no hurry to buy or make a replacement, try it.
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Maybe thats the secret to your success :bow: I've had GDS manifolds on all my previous Z's including the Samuri which had a GDS stainless manifold & twin pipe system. At the moment I have the choice of using either the GDS or the Nismo manifold which ever one I fit I'm going to have to have a system made up, thinking on I have a GDS rear pipe aswell so I would only have to have the section between the manifold & diff made up, the cheap option :D been quoted £600 for a stainless system to couple up to the Nismo. I will wait & see what advise comes along. Thanks for that Rob certainly food for thought in these hard times. Anyone want to buy a Nismo manifold :lol:
 
When I bought my GDS system 9 years ago (off Dean Botterill) I didn't know much about Z tuning (still a novice now) but it seems to suit my engine. However I've not tried anything else.

Also in connection with Skids comments the final collector is a long way down the gear box:thumbs:. The only negative point is that the whole manifold and collectors are one-piece so when I need to drop the box (done that 4 times) the manifold and carbs have to come off. Jay take note!

Also my manifold was made for a tripple Weber set-up where the crankcase breather has to be removed. I have SUs and so could keep my breather in place. I went to see Graham at GDS and he re-routed my No1 cylinder primary to miss it.
 
Well as my exhaust has started to blow (correction - fallen off!:D), and all these threads on systems and manifolds, I decided to go mad and book myself in to a fabricators who are going to custom make a whole system for me.

This company came 'highly' recommended by a number of people, and must be very popular as the earliest they could take the car was the back end of July!

There were some stunning cars in their workshop, including a 300SL Roadster, and I have to say I am very impressed so far.

The nice chap quoted me about £600 for the header and about £350 for the system. Exact details to be decided, but to be fair, they are the experts, and I trust them with it. The collectors 'will' be further back though! :D
 
Dale you're in safe hands mate, AAS built my complete system including fabricating all my charge cooler and waste gate pipe work, The system them made me was a full 3" stainless system that was both quiet and flowed well enough to achieve over 500 bhp (my old Pulsar gtir).

When I'm better off and have had my car on the road for a while I will be going back to them for the full Monty lol, Mind you they did say they would never take on another set up like mine lol so maybe its best if you don't mention me :eek::lol::lol::lol::lol:.





Rob
 
Thanks Rob. I'm pretty pleased with the price too, I can't wait 'til it's done.

I'll remind him of you when I'm next down, if just to see the look on his face! ;)
 
I will be very interested to see the results
I know they are very reputable but one thing many companies overlook is just how precious 10hp is on an NA engine (which are becoming rarer in performance cars) and as such they tend to forget that us "proper tuning" folk dont have girly boost controllers that we can just turn up or down:p...reiterate to them the importance of gas speed and scavenging.......... please;).
 
SKiddell said:
reiterate to them the importance of gas speed and scavenging.......... please;).
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Will do Steve.

I have no idea the kind of power the car's producing at the moment, but it's certainly not enough! :p

It's an L28 with 240 SU's and a magnetic air gap ignition. There's no induction kit on it, so that's something I need to address.

After looking at the exhaust system that's on now, the chap said I'd get a good improvement on power with the one he'll do for me.............. which is nice. :) He said that the header he'd make would go further back down the car, as the one on now ends at the firewall.

I think I need to do some reading up on the subject, so I don't seem like an idiot when I'm next there! :eek:
 
I will be needing to fit a manifold & system very soon, so will have to use the 1 3/4 nismo I already have as there is no chance of getting anything else at the mo. Would I be better off fitting a single 2 1/2" system with single rear box & the correct collector setup or a twin pipe system with 2" pipes straight through with up & over tail box.
 
Doesn't appear to have strangled mine AND I get into Castle Coombe without buying an extra silencer !
 
SeanDezart said:
Why not a centre box ? What about.....'noise' and not getting onto circuits ,
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I've been advised no centre box by DJ & Skiddell, I am not a circuit racer anyway, just enjoy a very fast road going 240, no stereo required ,triples & exhaust note are the music :D ;) we have the roads around here to do it :thumbs: Top Gear do alot of filming around here + other motoring programs, many car mags use the area also, & Mclaren used to test the F1's around here aswell, when they where testing a mechanic wrote one off only 40 mles away.
 
I have a centre box too. When the Z is ticking over I can feel every beat out of the back, can't restrict it too much then.
 
Weird Gwyn 'cos Dave fitted mine with the centre box. The spec. was a road car with no trouble to pass db tests so maybe that's why.
So ideally, just a back-box - a true silencer or just a baffle box ?

C'mon, you ARE going to do some track days are you not ? You'll never fully exploit it on the road.
 
samuri-240 said:
I've been advised no centre box by DJ & Skiddell, I am not a circuit racer anyway, just enjoy a very fast road going 240
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There a lot of people who talk theory and indeed know their stuff and put it to good use, these two included. However a reasonably modded 240 can still produce some useful power and provide an enjoyable driving experience. Not everybody is capable or knowledgable enough to prepare their cars to competition standards. And to be honest it only REALLY matters if you are competing. Getting the last few 'horses' out of the engine can lead you down a very expensive and tiresome road.

Track sessions - some people are intimidated by these and if you're not happy then no point in doing them. What I would say is that if you are driving a quick 240 hard on the road your are living dangerously, more dangerously than doing a well controlled track day.

So in summary a centre box should not be discounted for a fast road car.
 
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