Was the dynomax muffler 5" diameter with a 3" core?

 

4" straight through dynomax bullet.

 

same thread you say? brilliant!

with 2 RB mufflers, it'll be quiet

 

Yeah, I had to use the beehive bolt on Gavin's exhaust when his O2 sensor was bad. The threaded part is even the perfect length to keep the threads clean.

I hope it'll be quiet. Driving around for a year with all that racket in the back, well, coming up through the storage bin area, made me hate it. If I gotta spend 450 to quiet it down, that's still cheaper than an RB system (350 for mufflers, 100 for pipe and flanges etc).

Sorry Adrian, I won't muddy up your thread anymore. I'm just so excited to finally get started on my 3" today!

 

So today I cut out the expansion chamber. the exhaust now uses the same collector and collects into 3" and is 3" akll the way out the back. I will dyno soon to see if there is a difference. It clearly doesn't have the TQ peaks like it used to. Before you could feel the 3 tq peaks durring a pull. Now it just pulls straight all the way to redline, but it doesn't feel quite as fast at redline. Only 1 way to know all else is speculation.

 

Update: Just set my appointment. 11 am tomorrow at Drift Office. same place I did 189.65 Guess this should put to rest if the expansion chamber works or not.

 

good work!

 

I'll let the pic speak for itself make of it as you will.
Same timing, same jetting, 8* cooler, 39% more humidity today.
The blue line was the last time I was at Drift office. and the redline is today al the data is in the photo.

here's the problem. I just didn't take out the expansion chamber. I also changed the header. i was using an old rotary Engineering header painted with high heat paint and wrapped. The new header is an ISC header that has been ceramic coated. You can see the ISC header is straighter off the block and makes a better more gradual turn. I think that's where I picked up the extra 4 ft. lbs. of TQ. Plus you can touch the new header it's soo much cooler in the engine bay now. I think the header added the extra power. I think the expansion chamber was acting as an exhaust box in the same way that the 3" magnaflow that replaced it is...

 

interesting, when you said it didn't have the peaks, i assumed it was making less power, interesting its just flatter TQ curve.

so the ceramic coating works better than the wrap? that's interesting too.

 

I assumed the same thing. The TQ curve is just so much flatter I just assumed it was slower. I was losing oil pressure above 6500 RPM so I stopped and pulled it off the dyno. I am running Redline 5w20 with about 2800 miles on it, so I wasn't willing to push it. I'm going back to 20w50 from now on. It was holding 90psi steady until 6500 then it would drop to 60 by 7500. scary... When I get to Cali (10days!!!) I'm going to throw some bigger chokes in the car and see if I can get 200whp.

Last header I painted it with 1800* BBQ paint inside and out. Baked it on 3 coats then wrapped it. I was so impressed that I could put my hand near the header when the car was running. Now with just a ceramic coating I can actually touch the header! It's amazing... The tech at Driftoffice told me they had a turbo manifold coated by them and saw a drop in the temps around it by 300* no bullshit 300*. It was on a race car they built and it was overheating the brake fluid until they had it coted. Awesome prices too. $120 b4 tax for my header.
www.performancecoatings.com

 

When I switched from the RB road race header to the same ISC header I did get a small hp increase. It is a better designed header.

It's a little rich on the top end. Try a main air corrector that's half a step larger.

 

yep I know it's rich I had a whole hour on the dyno, but as i stated earlier I was losing oil pressure so I took it off they dyno. I'll tune it when I get to cali. With bigger chokes it's going to want more fuel anyway.

 

this time, be sure to call me bro, hope your still have my #. I aint far from holllyweird

 

Dude, I'm moving for good. Not just a visit this time.

looks like I need to edit my sig. .3 more whp! LOL! It's the 4 ft lbs of tq I really like though.

 

what did you do with your old header?

 

keep the washington registration, even if you don't have to smog the car, CA is expensive and a pain

 

Any pictures of the Magnaflow 3"? Or a part number?

 

how expensive? WA is $120 a year...

 

just some plain old 9x4, 20" long case, 3" in and out aluminized magnaflow. It doesn't matter. just get what you think will fit.

 

really? WTF... my FC is $69 a year...

if you wanna know how to pass smog shoot me a PM, its not hard you can even keep the weber

 

Cool, thanks man.

 

sitting on my garage floor. $60 shipped to your door.

 

Interesting read. I have been thinking about going with a custom exhaust off my RB Road Race header to see just how restrictive it is. Right now I am at 160 rwhp with the mods in my sig. Ideally I would like to keep the noise down as well.

Could you post up pictures of the new exhaust and list the parts so it is all in once place?

Thanks,

Greg

 

I am hoping to replicate your set up and run it back to back with my RB setup.

(I would be retaining the RB Road Race Header)

 

So you replaced the 4" Center section muffler with a 3" now?

I reallly can't wait to personally jump back on the dyno again and see if I can break 180 with my 12a