Does it really make that much of a difference? I hear a lot of commotion about 2.25 and bottlenecks lately in the TYPE R forum...I mean is there going to be enough difference in power gains for both cases: 1) mildly tuned vehicle (i/h/e/fuel/cam gear tuning)

2) heavily modified motor (headwork/cams)

I mean how much HP are we talkin going from a 2.25" catback system versus a 2.5" because I'm having so much trouble finding mainstream exhaust manufacturers such as Greddy or HKS supplying those diamaters...the only ones carrying large diameters are Type One and Spoon and Kakimoto right now..in 63mm variety... I wonder if the extra $$$ and hassle are worth it..especially the noise levels going up when stepping up to a larger diamater. I"m running a Jdm 2.5" header going to a 2.5" carsound cat or 2.5" Type one racing convertor..and right now need to know what B-pipe/midpipe i should go for....please give me your input and REAL world data for backing...thanks.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by IN2VTEC &raquo;</TD></TR><TR><TD CLASS="quote"> 1) mildly tuned vehicle (i/h/e/fuel/cam gear tuning)
</TD></TR></TABLE>
No

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">
2) heavily modified motor (headwork/cams)</TD></TR></TABLE>

yes

 

any more details than just a 'yes/no' reply?

 

his answer pretty much sums it up..

imo its not even worth i/h/e or any mild bolt ons.. car will still be slow, either make it fast or keep it stock for street setup. unless you get your money back by racing the car and benefit with these few extra where rules allow.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by IN2VTEC &raquo;</TD></TR><TR><TD CLASS="quote">I'm having so much trouble finding mainstream exhaust manufacturers such as Greddy or HKS supplying those diamaters...</TD></TR></TABLE>

Why does it need to be made by what you refer to as a "mainstream" manufacturer? SMSP isn't what most would consider a "mainstream" manufacturer (and that's one of the things I like about Dave and his products), but he produces some of the finest exhaust components available for your car.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by IN2VTEC &raquo;</TD></TR><TR><TD CLASS="quote">especially the noise levels going up when stepping up to a larger diamater.</TD></TR></TABLE>

Dave's 2.5" straight-through cat-back, by all accounts, is anything but loud.

 

stop showing off gramps

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by George Knighton &raquo;</TD></TR><TR><TD CLASS="quote">I guess it's time to drag this old chart out again.

</TD></TR></TABLE>

im not being an *** but wats this dyno graph suppose to show us???

 

thats what a quality exhaust can do if you're willing to spend the loot

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by eg cookiemonster &raquo;</TD></TR><TR><TD CLASS="quote">

im not being an *** but wats this dyno graph suppose to show us???</TD></TR></TABLE>

And I wonder how much difference there would have been with a good 2.25" exhaust. I'd love to see a comparison of the two on a mildly modded motor (like 85% of the folks here have).

 

haha yeah...what Mr. Knighton forgot to mention to tell us was that he has a port n polished head and cam gear tuning and hondata

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by IN2VTEC &raquo;</TD></TR><TR><TD CLASS="quote">haha yeah...what Mr. Knighton forgot to mention to tell us was that he has a port n polished head and cam gear tuning and hondata </TD></TR></TABLE>

191 ponies is kinda hard w/ just i/h/e

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vtec.dc2 &raquo;</TD></TR><TR><TD CLASS="quote">his answer pretty much sums it up..

imo its not even worth i/h/e or any mild bolt ons.. car will still be slow, either make it fast or keep it stock for street setup. unless you get your money back by racing the car and benefit with these few extra where rules allow.</TD></TR></TABLE>

Well an R with a proper I/H/E setup (heck not even the good stuff in some cases ) is good for mid-high 13's. Not to shabby considering your not compromising relability and 13's isn't exactly the slowest thing in the world for an everyday street car.

 

IMO any vtec b-series should run 2.5" collector'd header and exhaust. Seems to produce the best results from all the dyno's ive seen. Works great with my very mild b16 too.

 

went will 3' Exhaust would be needed in an all motor set up ...???

 

GET a rocket exhaust will improve the performance yo

 

If you have a 2.5" collector header, there's no reason not to get a 2.5" exhaust. It's worth it, a properly designed and sized exhaust system will blow away one that isn't sized properly even on an otherwise stock motor.

 

2.5" certainly doesn't hurt. I think that's been established. Hell, my B16 with 2.5" exhaust from the header collector-back (with <u>no</u> bottlenecks) made more torque (albeit only a few lb./ft.) than most other B16s I've seen.

Plus, you won't have to change exhausts if/when you mod the engine more.

 

All I can say:

I`m using 60,5mm inner diameter catback, a hjs racing cat and a modified jdm header on a jdm engine..... And the power output is like you are driving a different car compared to a stock itr. I am dealing with Hondaz and use to drive stock itr`s from time to time....They feel so damn slow compared to #05874. I need 1st, 2nd and 3rd gear to pull three carlength between mine and a stock R.

The power came with the b-pipe.... going 240....250....260...and still accelerating (with Kenji ECU)....

With stock exhaust, the speedo dies at 240... really.

 

.....I've tested the stock itr exhaust vs a mandrel bent 2.5" exhaust and 2.5" makes more power. BOTH exhausts make less power than open header however..... Perhaps 3" would be the way to go now? STOCK itr motor, btw.

 

bump

planning on upgrading my exhaust soon, this is good info

 

Im thinking about making a custom exhaust this weekend. we shall see how it turns out

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Black R &raquo;</TD></TR><TR><TD CLASS="quote">.....I've tested the stock itr exhaust vs a mandrel bent 2.5" exhaust and 2.5" makes more power. BOTH exhausts make less power than open header however..... Perhaps 3" would be the way to go now? STOCK itr motor, btw.</TD></TR></TABLE>

Way back when, on RStoR's car we lost power with an open exhaust versus the 2.5". On sgt's 231whp B20 there was no power difference between the 2.5 exhaust and open header.

 

Have any of your tests included testing the 2.25" Magnaflow systems you also offer, alongside your custom 2.5" ? I realize this might not be your ideal marketing approach, but I was wondering, as I searched and found an earlier post where you offered them as an alternative for mildly modded ITRs (I/H).

 

No I haven't. The reason being is that I have other prototype pieces to test that I need to determine if the changes made any improvements. Something like a 2.25 vs 2.5 exhaust comparison isn't something where I'd say to myself, "I wonder if that may be a little better" where my experience tells me otherwise. I really think the question becomes who builds the best flowing exhaust, that's the lightest and more importantly the quietest. An extra $25-$50 up front will probalby be worth the cost of future tickets and police hassles.

Testing is key, though. That's why I'm working on reorganizing my business in order to get the proven pieces to market quicker and hopefully at better prices and concentrate on more R&D. I hope to be bringing some new items to the market, other than just the exhaust, by the end of the year. Some of these will be used on my H1 Honda Challenge car.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SMSP &raquo;</TD></TR><TR><TD CLASS="quote">I hope to be bringing some new items to the market, other than just the exhaust, by the end of the year.</TD></TR></TABLE>

I'm intrigued Dave - any hints as to what sort of items they might be?