Id go for the up-pipe and the inlet first... What about a magnex bb, anybody got one of them that you can try as they are supposed to be quite, quiet. If your getting an up pipe I would look at the MRT one, or at least look to get one with a flexi joint (see other thread)... Is the inlet pipe to the turbo quite restrictive behind the powersteering pump on your cars... Do you just use a panel filter??

David

 

Hi John,

I can't really comment on EGT's etc but I fitted a Magnex BB (not too loud but a nice note) and this increased standard boost about 0.5PSi (hard to tell as my gauge is a defi reading in KG/cm
I then had the Dawes put on (gone now ) by this time I had a full Magnex Decat system. The other half was fed up the car wasn't popping and loud so forced me into getting a scoobysport BB. This is much louder, but lots quieter than the Blitz. Having fitted that I had to turn my Dawes down as it increased the boost to the point I hit the fuel cut!!! (had been running about 16.3-16.5Psi on the magnex).

Dunno if its any use to you, just my experiences.

Cheers
Neil.

 

I used a magnex prior to making my own system up. It was quite restrictive, fitting a straight through dropped my EGT considerably.

I use a Jetex 3" bore straight through absorbtion type box fitted with the original subaru inlet and outlet pipes. It's a bit 'boomy' at low rpm but quietens down at 3000+ RPM (JB, when you were last in my car it had no silencer at all )

I believe the mongoose 3" twin box system is straight through. I had one on my Cossie and it was not at all noisy with very low back pressure

May be just what you're after ?

Andy

 

Was that with the bung fitted in the backbox or not???

There is a sound reducing bung.. how much it reduces power I don't know..

I only know from speaking with Markus who has just fitted a Blitz.

JGM

 

John,
Would you be interested in trying my Magnex (3 1/2" tailpipe) when I next visit?
Chris

 

john,

has it stopped overboosting yet ,told you it would make a difference.

has delta dash shown any other changes other than just to boost peak,does it hold more higher up or have you already remapped to Tek431 ?.

was impressed with your egt's considering your speeds ,also will have to try and get a silenced centre,your prodrive one really quietened the blitz down.you should try it with a straight through

I have tried both oval and round Magnex b/b's on my car.good fit and good sound,especially off the oval but I could not feel any performance gains unlike with the blitz.

 

Andy, i have the mongoose, and as you say, it is a straight through with 3" bore. is twin box with twin dump downpipe. very impressive gains just from that alone

cheers, ian.

 

Thanks guys. I'll have a little think. I still have the boost tapering with the map so I don't know whether it would hold more - I think I will just put the intercooler on and leave the map conservative and see how it works on the track.

 

Hi John
Just to add on the above that after I changed the OEM headers with PE stuff (Maxim Racing like), I have a significant boost pressure drop (about 1 psi) especially below 3000 rpm (more than 1,5 psi), but I can't comment about EGT as I haven't yet fitted my EGT probe.
Although before the PE exhaust manifold I had usually from -1,5 to -3,5 knock correction between 4-5300 rpm and now I have always 0 which is due to reduced EGT and probably lower boost pressure!
Car is MY00/PPP and very soon I'll add a Magnex downpipe with the hope I'll gain some of the lost boost pressure and low down torque. Forgot to mention that now it pulls all the way to the red line like non-aspirated engines do!
I'll send you some of my log files after an ECU reset when I saw first time -4 knock correction and before/after the new headers just to compare.
Cheers
JIM

 

T-uk bullied me into trying his Blitz Nur Spec instead of my PPP backbox for a few days

Boost peak is about 1 PSI higher in the same conditions and it is quicker despite the extra noise. Very loud though and I could not live with it day to day long term. It was like uncorking the whole thing, I expect a backbox alone would not cause this benefit unless it was a big restriction compared to the rest of the system.

Anyone tried any other back boxes that obviously frees things up beyond a PPP backbox - ie lower EGTs, high peak boost etc that are not so loud? I think it goes well because it isn't quiet! I'm not just going for something because it sounds nice or someone says it felt a bit quicker - I want to know it is actually less restrictive.

It would be nice to fit a new up-pipe and a large bore intake pipe as well probably. Any experience with these in terms of alteration in boost/fuelling/EGT etc?

[Edited by john banks - 6/11/2002 10:11:10 AM]