Pre 87 RMB
#16
Administrator - "Tyson"
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Scratch next week, Injectors won't be done until the first week of July........anybody want to loan me 8 L-Jet injectors?
#17
Inventor
Rennlist Member
Rennlist Member
Replace the Panzer factory muffler with a Monza twin resonnator tip, or go straight out the back!
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Rufus Sanders said: "Porsche got the exhaust right on the pre 87s"
That's true for the stock system. Although the L-Jets run a bit lean.
Opening up the exhaust by itself may not improve power. Upping the base fuel pressure about 5PSI helps. Advancing/syncing the cams transforms it.
Opening the exhaust is akin to retarding the cams, making the engine breathe better, but the lack of back pressure means you're losing effective compression on the low end. Advancing the cams helps restore this compression.
But you can only go so far with the wimpy L-Jet cams/intake. All the work I've done on my US '81 (9:1) 4.5L has only put me on par with stock US 83-84 (9.3:1) 4.7L's!
...
Rufus Sanders said: "Porsche got the exhaust right on the pre 87s"
That's true for the stock system. Although the L-Jets run a bit lean.
Opening up the exhaust by itself may not improve power. Upping the base fuel pressure about 5PSI helps. Advancing/syncing the cams transforms it.
Opening the exhaust is akin to retarding the cams, making the engine breathe better, but the lack of back pressure means you're losing effective compression on the low end. Advancing the cams helps restore this compression.
But you can only go so far with the wimpy L-Jet cams/intake. All the work I've done on my US '81 (9:1) 4.5L has only put me on par with stock US 83-84 (9.3:1) 4.7L's!
#18
Nordschleife Master
Thread Starter
Por Ken - dunno if that applies to a Euro being that I cannot advance the timing. I would rather not run open pipes because of the DB levels. I think w/my intended harware set up - I should be good to go. I just need to get to it!
Thanks for the heads up!
Thanks for the heads up!
#19
Inventor
Rennlist Member
Rennlist Member
Sorry Drewster, I didn't pay attention to the fact that you have S2's, and I was more responding to what Rufus said.
After reading the entire thread, the muffler you picked looks cool.
It's easy enough for a muffler shop to join the two pipes together at the muffler when they're welding it up; I've made a couple of collectors with 3" pipe.
You could also just have a pair of single resonator tips put on the end of the pipes.
Just for reference, since you already have HTD gears on your engine, it would be easy to put in 32V adjustable cam gears like I did (just look at my current avatar).
After reading the entire thread, the muffler you picked looks cool.
It's easy enough for a muffler shop to join the two pipes together at the muffler when they're welding it up; I've made a couple of collectors with 3" pipe.
You could also just have a pair of single resonator tips put on the end of the pipes.
Just for reference, since you already have HTD gears on your engine, it would be easy to put in 32V adjustable cam gears like I did (just look at my current avatar).