A&Q about 350Z
Q:
Righty lads and ladies, just took hold of a brand enw Jetex system or the mk1.
I bought the 2.5" system(29-H5) with the 70-90 polished tail pipe so it'll look a little nicer than just a pipe sticking out the back.
Anyway.....
Just opened the box up, had a look at the pipe that goes over the rear beam. Hmm, nice, 2.5"
Then had a look at the centre box, only to find that the bore going into it fits the standard down pipe(which I was going to remove and fit a new 2.5" inlet pipe), but the exit of the box is still around 2" and less, tapering open into a 2.5" pipe. Same goes for the back box. Pipe in is 2.5", tapering down to less than 2" !!
So in effect the boxes are strangling the system down to less than 2"
Any thoughts on this as the system is advertised as 2.5" ??
A:
Never had a problem with the Jetex 2.5 Rally system, which has a proper bore for the mid section entry.
Also the two pipes on the left of the pic are the one pipe with the Rally system.
A:
The middle and rear boxes have a really small bore to it. I've measured it at 1.750" compared to that of what they are selling at 2.5"
Quite disappointing as they clearly say 2.5" system. They should be saying:
1 - 2.5" pipe
2 -1 3/4" bore boxes
A:
I guess strictly speaking it isn't a complete 2.5" bore exhaust system through-out, but if compare it to the standard setup, it does free up the bore from 1 3/4" to over 2inches and up to 2.5". So it will free up the restriction a little, just maybe not as much as you said. The reason the centre box is 1 3/4 is to allow for after market fitment and to simple bolt onto the existing CAT/downpipe.
On another note, do you know the outer diameter of the 1 3/4" pipes, presuming the bore is the inner diameter.
A:
Had a reply from Jetex.
Basically the only 2.5 system they do is the T26-h/k systems.
The others they class as 2" although it's the O/D thats 2" while the bore of the boxes is about 1 3/4"
I was aware that the start of the middle box was smaller, and was going to replace it with a larger bore connecting pipe, but with the bore of the box being so small it's pointless, as the system has already been restricted,so no matter how big you go further down the line you ain't getting any more gases through that first small bore.
On another nore, although the Magnex doesn't fit like it should, it has a proper straight through bore, which isn't smaller in the boxes than they are on the pipework.
A:
Had a reply from Jetex.
Basically the only 2.5 system they do is the T26-h/k systems.
Pretty sure that's the Rally system.
If I were to buy a high flow exh for a Mk1, there is only one choice imo: that system.
A:
I had a custom made 2.5" stainless from longlife which is a cracking one.
A:
Sorry Mart,
i think i told you the 2 systems were the same except the tailpipe on the rally system wasn't stainless, as thats what they told me when i ordered my rally system.
Also the rally system actually bolts to the rear floor, which is a much better design, with less stress on the joints. If you're not bothered about the tailpipe i'd swap it for the rally system.
Ian.
A:
I phoned Jetex a few weeks back and he explained to me it wasn't a true 2.5" system.
So I went for the Supersprint 16v instead.
A:
I've ordered the Rally system instead.
Top bloke Jason at JSW automotive is sorting me out and is having the other picked and and the new one delivered in a next few days :)
A:
i have the rally system on my mk1.
its mild steel, 2.5 inch all the way. first section is a silencer, and has a bracket to bolt to the floorpan with 2 rubber mounts. the second section looks a bit like the one in that first pic just without the brackets and fatter, it fouls on the fuel tank heatshield and the rear beam a bit, but does fit. and the rear box is also mild steel, has 2 hangers at the back of the backbox and has a mild steel tail pipe that is clamped on. a bracket is then included with the clamp for the last hanger.
problem i found, dispite the tight fit, is that if you mount the first section to the body, it sits to low, and i managed to rip the 2 rubber mounts off that they supply you with to screw through the floor pan. this was with an ashley 4 branch and polly engine mounts on a 16v engine. the way they expect you to mount it does not allow any front or back movement of the exhaust at all. i modded mine to replace the stock mounts with a normal rubber hanger and its been fine.
A:
I fitted one of those joints with the 2 large springs (1 either side) to my exhaust as it was cracking on the mk1.
A:
does anyone know if the 2.5 bore not being 2.5 aplies to the mk2 system?
A:
Also the rally system actually bolts to the rear floor, which is a much better design, with less stress on the joints.
Ian.
Welll until the bolts all shake loose Good no nonsense exhaust tho!
....and as for the Jetex 2.5" stainless mk2 system, that's deffo 2.5" bore through at least the resonator box as I peered inside when I ditched it at teh weekend.
Thread title not too fair eh Sh@g ?