The collector on header #3 was extended to match the exhaust since Header #2 was much longer than #3.

Remember your dyno runs are really just that, yours and should only be used to compare mods on your car (same engine) and tested near the same conditions (same day) on the same dyno.

I know an ITR that dyno'd at a 10whp difference between 2 dynojets with the same set up. BTW, the dyno that was used for Corey's car was the dyno that recorded the lower numbers for the ITR. So just be concerned about the difference you get after making a change.

One other thing, never never use dyno numbers to compare a CAI.

 

No. I haven't dynoed my car again in over a year now. I'm in Solo2 STS trim, so an aftermarket cat is out of the question for me. Next time I go, I'll have at least: AEM CAI, Mugen Header, Mugen Cat-back, and V-AFC. I think that should be good for pretty darn close to 180 SAE WHP... I guess we'll find out!

Andrew

 

You're correct... just to clarify though, the ID is 57mm (2.25").
The collector "flange" is designed to bolt up to a stock cat flange, but that's fine as long as your running a high flow 2.25" cat. Then this setup would optimal.

However, Mugen's cat back exhaust does have a restriction...its the 1 foot section of b-pipe from the resonator to the cat. This pipe has an ID of 51mm (2") where as the rest of the piping is closer to 60mm. I have the header and exhaust in my room waiting to install, so my measurements are based on the real thing...no guess work here. Hope that helps.

David (SMSP):
King claims that Mugen designed the 1 foot smaller diameter section of the b-pipe for scavenging and exhaust tone, rather than just to bolt up to a stock cat. Is there any truth in that? And, would you recommend replacing that 1 foot section with a larger pipe to eliminate the restriction?

Thanks.


[Modified by Kool-Lude, 3:59 PM 1/7/2003]

 

I would like to see how the Greddy Header does in comparison..oh well.

 

Isn't the main tubing 60mm OD? Tubing is spec'd by the OD not ID.

I think we just found a donor Mugen exhaust system.

Don't know the design of the system. If that's what they say then I would take it as true. If the pieces are engineered as a system then maybe you should keep it as is.

 

i wouldnt mind but it all depends on when you plan to do it..

 

Well I can build the full system on Corey's 4th gen or there's a guy who's been on the build list since Oct and he's got a 5th gen and lives about 2 hrs away from me, so I could build the system on the car also, if he's willing to let me use it.

Now I'm pretty sure the cross memebers are the same on both the 4th and 5h gen cars. What is different between the 2 gens. Wheelbase, exhaust tailpipe, etc?


[Modified by SMSP, 9:54 AM 1/7/2003]

 

The Mugen header actually does have a 2.5"(60+ something mm's) collector(2.3" inner diameter). And I bought a 2.5"(again about a 2.3" inner diameter) testpipe which bolts up to it perfectly. SO I am very skeptical. If the header is price well under the Mugen($975) then great. But the Mugen header with a cat and(one had the b pipe modified or removed if i am right) cat back exhaust has shown to already make 170-180whp and about 140-145 ft. lbs. of torque from 3 different dynos I have seen on some stock setups. And none of them had a lightened flywheel either that I know of. They were stock engines minus an intake basically. SO I think the work your doin is great assuming your headers are going to be signifcantly cheaper than the Mugen.


[Modified by Ritteri, 6:00 PM 1/7/2003]

 

For mild comparison's sake. I dyno'ed my last Prelude (95 VTEC) with AEM CAI, Greddy header, stock cat, 60 mm Apexi RS exhaust (muffler was disconnected...but still full pipping) and I dynoed 183.5 whp and 149 ft-lb tq. I also had a V-AFC, but no o2 reading was available so we just "guess leaned" up to 5% in the higher rpm ranges.


[Modified by Mike95lude, 10:26 AM 1/7/2003]

 

That is what I heard...I have not measured the OD. I said "closer to" 60mm in my post above...oh well, didn't mean to be confusing. But I can tell you that other than the b-pipe to cat section, the openings have ID's slightly greater than 57mm.
Road trip? I don't think so... but I would if you were closer.
So if I keep it, is it possible to customize a 2.25" (or 2.5") cat so that the outlet tapers down to 2" ID and the overall cat length is the same as stock? Smooth transition is what I want, right...or is the difference in my setup not significant?



[Modified by Kool-Lude, 6:37 PM 1/7/2003]

 

The Mugen header has a 60mm (2.36") OD collector. Assuming the same wall thickness, a 2-1/2" OD (2.37" ID for 16g) collector will have an area 11.4% greater than the 60mm collector.

I know you are skeptical and other may well be also. I haven't said it's better than the Mugen, I hope it will be, but since I haven't tested it against the Mugen I can't say either way. If and when it gets tested against the Mugen it will be the production version so everyone know exactly what they are getting.

 

werent your numbers the 'actual' whp and not 'sae corrected'? maybe im wrong.. i thought there was discussion about it.

 

Dave, will this header be available for a 5th gen SH sometime in the future?

 

Im not really skeptical of performance.I am sure its going to be on par with the Mugen obviously. Just that the price would need to be better than the overpriced Mugen if you get my drift! The Mugen inside diameter is exactly 2.3" btw. Maybe just a tad over that with my scale ruler. The outside diameter is about 60.9mm if I am correct. I have a really good engineers ruler, im gonna find it and use that to measure it for an exact ID and OD. THe Mugen does use that flex material too on their header like the stock, which is a larger diaemeter too.

 

The 60mm OD came from King Motorsports.

 

Here is what King emailed me.

-----Original Message-----
From: King Motorsports Unlimited, Inc.
[mailto:tech-staff@kingmotorsports.com]
Sent: Thursday, June 20, 2002 11:44 AM
To: Greg Pensanti
Subject: RE: Mugen header and exhaust diameter

Greg,
The mugen header and exhaust bolt right up to a stock length and stock
diameter flanges. Exhaust header inner diameter at the flange is 57.32mm. OD is
60.62mm. Mid pipe Diameter at the flange is inner 50.76mm OD is 54.04mm. Hope this helps.
As to the cat just, make sure it has an o2 sensor port.The choice is
yours. Call if questions

Regards
King Motorsports

 

No they weren't. Actual numbers were up in the 188-189 whp range with 150+ ft-lb torque. I have both graphs.


[Modified by Mike95lude, 1:15 PM 1/7/2003]

 

ahh. my apologies.

 

It's ok.
I have a feeling SMSP's header will really stand above the rest when used in more serious all-motor buildups that modify the internals. It's actually fairly guaranteed due to the header having larger exhaust gas volume capability due to larger tubing than the competition has.

Doesn't King Motorsports "modify" the Mugen header to be compatible with the exhaust sizing of USDM Preludes? If so, its a pretty damn big waste if you're really serious about performance. I'd look for an authentic JDM Mugen header.

 

The 5th gen Mugen header was designed for the TypeS Prelude. The one sold in the US for the TypeSH is the exact same one sold in Japan. It bolts right up with no modification. The Base Mugen header is modified, but only for collector length to be the correct length to meet the cat. The US Prelude Mugen header is not modified in piping diameter.

Andrew

 

You wouldn't happen to have pics of the mugen unit, I have actually never seen one..

 

Corey,

Here's some pictures that I dug up. Credit for this page goes to Abe Shige, too bad he doesn't update it anymore.

http://www.gotrice.com/users/shige/k...ani/index.html


[Modified by TimeRacer, 10:17 AM 1/8/2003]

 

I don't know where I saved my pre-install header pics. Shige's pics are better than mine were anyway...

What ever happened to Shige Abe? He was one of the OG Prelude people way back in the VTEC.net days. Does he still have the Prelude?

Andrew - The Patented Multi Jumping makes you Crazy Sprinter and Spin Happy.

 

I think what we'll try to do is dyno the following set ups, 4th or 5th gen still undetermined.

1. Stock header/cat/cat back
2. SMS Header/2-1/2" Carsound Cat/2-1/2" Custom cat back
3. Mugen header/stock cat/Mugen cat back

These will be done on the same car, same day and same dyno.

 

David,

Any way that you can provide a fourth dyno using the Mugen products and a carsound 2.5" cat? I am considering getting a carsound cat for my 5th Gen, if you fab one up for the test I'll purchase it from you when you're done with the tests. Let me know, PM or e-mail me at dougiemd@attbi.com about it.