Sound requirement and straight-pipe [Archive] - Improved Touring Racing Forums

jc836

01-15-2003, 02:18 PM

I have no idea what the actual dB level will be for a fully open exhaust-except very loud. Some tracks generally will not let you run without some sort of muffler. There have been a few pictures of DIY "cherry Bomb" exhausts recently on the WEB. I would also doubt that they meet the CHP 95dB rule let alone the SCCA measurement rule. You might want to talk with someone from Flowmaster or DynoMax about your project. I do know that Thermal R&D tries to stay on the edge of 95dB with all of their products. I did a test here of the Thermal on my 99 Prelude and at 1 meter perpendicular to the center of the resonator I read 94dB max at 4000 rpm. What it is at the tailpipe-I have no idea-but definitely quieter.
Good luck

------------------
Grandpa's toys-modded suspensions and a few other tweaks
'89 CRX Si-SCCA ITA
'96 Civic HB Just cruising daily
'99 Prelude=a sweet song

Knestis

01-15-2003, 03:08 PM

The laws of physics make it such that lots of variables change sound level readings - air density (so temperature, too), physical surroundings, and others - so it is impossible to say what kind of actual readings your car will register.

Heck, it isn't even likely that the same readings will result at the same track on different days. Remember too, louder isn't necessarily faster.

Kirk

Edit - and noise contributes pretty dramatically to driver fatigue, FWIW.

[This message has been edited by Knestis (edited January 15, 2003).]

davew

01-15-2003, 03:41 PM

I have run my crx w/ a 2.25" straight pipe as you describe, but with a dynomax bullet muffler on the end just before the trundown. It usually runs about 85-90db with a fresh muffler, and 95-105db once the muffler blows out. I just picked up a higher quality SS Borla bullet to try this season...hopefully it will be quieter and longer lasting.

I'd say that w/ a open pipe and no muffler at all you would be well over the 100db limit...but of course that depends on everything from your intake filter on through the whole motor and out the exh manifold, as well as enviromental variables, gas type, etc...

-dw

Fleetcare

01-15-2003, 04:31 PM

I found an interesting thing that says the exact specs on how each pipe should be.

I suppose email me if you want the info

Domino

01-15-2003, 07:22 PM

Originally posted by Fleetcare:
I found an interesting thing that says the exact specs on how each pipe should be.

I suppose email me if you want the info

Yes please. domino[][email protected] -delete the [] to email me.

ITR#231

01-15-2003, 07:25 PM

<font face="Verdana, Arial" size="2"> Remember too, louder isn't necessarily faster.</font>

Wazzat? Speak up Kirk, you're mumbling...

davew,

What kind of life did you get out of the Dynomax bullets?

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'88 CRX Si - ITA/PS2 road racer: Handles like it's on jack stands
'98 ITR #0231 - DS autocrosser: Handles like I sold it
'02 Jeep Grand Cherokee - daily driver/tow vehicle: Handles like a jumping castle

Richy Gonzalez

01-16-2003, 01:04 AM

I have the same setup, straight with Dynomax muffler and have been in the low 90 dbs.

Is Junktech out there? I know he redid his exhaust with a supertrap coming out the rear but I don't know what the dbs are.

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Richy Gonzalez
GB Racing - #24 ITA CRX (http://groups.msn.com/TheGonzalezFamilyRichySheilaandNyah/projectitacrx.msnw)
Racecar Sponsor: LAMIN-X Protective Films (http://www.lamin-x.com)

jasonb

01-16-2003, 03:29 AM

Originally posted by Richy Gonzalez:
I have the same setup, straight with Dynomax muffler and have been in the low 90 dbs.

Is Junktech out there? I know he redid his exhaust with a supertrap coming out the rear but I don't know what the dbs are.

Richy,

What diameter piping and muffler are you using and where does the exhaust end?

B Breon

01-16-2003, 09:49 AM

I have done a straight 2.5" exhaust with no muffler and a turndown as you describe. I was bumping 104 with it. Was forced to move the turndown so it was pointed a way from the sound stand. VERY LOUD, better have ear plugs. I put on a Borla Bullet and am at low 90's consistently now. NO noticealbe change in power and I can hear now.

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Brent Breon
Cendiv ITA #26
www.360racing.com

Richy Gonzalez

01-16-2003, 11:45 AM

JasonB,
I went with 2 inch pipe with the Dynomax round muffler at the very end with a turn down coming of the muffler itself. Also, it ends right behind the driver in from of the gas tank. The typical set up is 2.50 inch exhaust but I think that the smaller diameter will give a little more torque without losing any hp. ...but, I don't have any dyno numbers to prove my theory.

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Richy Gonzalez
GB Racing - #24 ITA CRX (http://groups.msn.com/TheGonzalezFamilyRichySheilaandNyah/projectitacrx.msnw)
Racecar Sponsor: LAMIN-X Protective Films (http://www.lamin-x.com)

Domino

01-16-2003, 12:36 PM

Originally posted by B Breon:
I have done a straight 2.5" exhaust with no muffler and a turndown as you describe. I was bumping 104 with it. Was forced to move the turndown so it was pointed a way from the sound stand. VERY LOUD, better have ear plugs. I put on a Borla Bullet and am at low 90's consistently now. NO noticealbe change in power and I can hear now.

I looked at the Borla Bullet on the website. Is this a muffler that doesn't allow you to put anything at the end, such as a turndown like on a typical muffler? I didn't want to go all the way to the back of the car (like stock) with the pipe. I want it to end right behind the driver. I don't think the Borla will fit underneath the middle of the car.

jasonb

01-16-2003, 03:39 PM

Originally posted by Richy Gonzalez:
JasonB,
I went with 2 inch pipe with the Dynomax round muffler at the very end with a turn down coming of the muffler itself. Also, it ends right behind the driver in from of the gas tank. The typical set up is 2.50 inch exhaust but I think that the smaller diameter will give a little more torque without losing any hp. ...but, I don't have any dyno numbers to prove my theory.

Did you use the Dynomax Bullet muffler? If so, what diameter Dynomax muffler did you use?

Richy Gonzalez

01-17-2003, 02:50 PM

JasonB,
The Dynomax muffler is 2.5 inches and I was able to stretch out the 2 inch pipe to fit snug inside the muffler, then welded it together. Then the turn down goes right over the 2.5 inch muffler end.

The Dynomax bullet (I think that's what they call the straight round mufflers) doesn't come any smaller then 2.5 inch diameter.

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Richy Gonzalez
GB Racing - #24 ITA CRX (http://groups.msn.com/TheGonzalezFamilyRichySheilaandNyah/projectitacrx.msnw)
Racecar Sponsor: LAMIN-X Protective Films (http://www.lamin-x.com)

ITR#231

01-17-2003, 11:58 PM

Does anyone have pictures of these set-ups? I'd like to see where you weld hangers and what kind of down-turns are being used.

My current exhaust setup is a custom "OEM + hacksaw" design, but it's too loud.

------------------
'88 CRX Si - ITA/PS2 road racer: Handles like it's on jack stands
'98 ITR #0231 - DS autocrosser: Handles like I sold it
'02 Jeep Grand Cherokee - daily driver/tow vehicle: Handles like a jumping castle

CRX Lee G

01-18-2003, 04:23 PM

We tried a lot of systems (Supertrapp, various cans, straight, long, short, etc) and shorter was better. We ran the straightest possible 2.5 tube with only a turn down at the gas tank but it blew 102-104db and would vibrate your body in the car at wide open. Put a Dynomax bullet on it and it blew 90-92db with good power. On another car, we had a 2.0 inch (available) open and it blew 106db and was really raspy. Threw on a Cherry Bomb for the weekend and it was like stuffing a cork in it, very slow. Larger tube is deeper, quieter and better.

FWIW, I am a be believer in spring mounted breakaway exhaust that won't wreck your header and drag if hit on a berm, etc. I turned my best laps at M-O after being run off the road while leading and stripping the exhaust away behind the header. The uncorked header was LOUD and fast, maybe a second per lap. I didn't get busted by the sound cops and finished. Just picked up the pipe at the corner station and only had to replace two 50 cent springs to the header.

SMSP

01-25-2003, 03:17 AM

Magnaflow has 4" round resonators in 2", 2-1/4" and 2-1/2" sizes with varying core diameters and lengths. These are just a little more costly than the bullets but won't blow out.

Tom Blaney

01-25-2003, 11:21 AM

Originally posted by SMSP:
Magnaflow has 4" round resonators in 2", 2-1/4" and 2-1/2" sizes with varying core diameters and lengths. These are just a little more costly than the bullets but won't blow out.

Did you use the 2 1/2" dia? and how long, my last car had a 4 " bullet that must have been 25 feet long. Did you dump it before the gas tank with a down pipe? Appreciate the install information, this was always a problem install on the last car.

Turned out that the kid that built it had the exhaust aimed at the rear lower control arm front bushing, the bushing finally melted on me at Watkins Glen, and I crashed out a guy and angered that really fast Saturn driver. So this time I want to get it right

SMSP

01-25-2003, 01:41 PM

I use a 10444 2" in/out with a 2" core for ITC cars. A 10415 2-1/4" in/out with a 2-1/2" core for ITA cars but open the outlet to 2-1/2" OD. On ITS cars I'll use a 10416 2-1/2" in/out. All these are 14" long x 4" round. 18" and 22" versions are also available if you need a little more sound control but all the cores are 2-1/2".

For a tunnel turn down I use either a mandrel bent 45 or a section of a U bend. Make sure the rear part of the tailpipe is not cut in a way to expose the opening when looking at it from the front. You don't want any air traveling under the car to be able to "see" the opening you'd rather the air rushing around the opening then hitting the opening. The same is true for side exit applications. Rear exits are a little more tricky since you want the tail pipe to be located in a low pressure area but the trick is finding that spot.

[This message has been edited by SMSP (edited January 25, 2003).]

HiRcc#21

02-05-2003, 09:24 PM

I have done alot of dyno testing different exhausts over the last 2 years and here is what we found:
on my ita crx, we found a reading of over 120hp (year old .020 over bottom end) at the wheels with this set up:
Using a new Landspeed Racing Powercore header, and a Magnaflow muffler (part# 10425). 2-1/4 in and out, 18" can.
If you measure from the flange of the header back 3" and install the muffler (edge of the can)into a 2-1/4" pipe,(with a rotateable flange and stock springs for hardware-like Lee suggested) the DB's ran at Nelson in Oct.'02 was 87. Lots of top end and it didn't hurt the bottom end either.
The straight pipe ends 7 inches after the linkage. (measured from the attachment point of the shifter to shift linkage arm.)We welded on a piece of round stock and bent it to the similar specs of a factory pipe, and used the rubber hangers to the factory "hooks" on the tub, and it works fine. No vibrations in the seat at full song.
We built approx. 15 different styles to arrive at this one.
The header, just released, gave us 2 hp over the old DC 4-2-1 with no header wrap.
Hope this helps you out... It does work!

Fleetcare

02-06-2003, 12:21 AM

Where do you find a muffler shop that will do this ?
I tried today but they wouldnt install anything or touch the car since it had no cat.. what gives and how do I prove its not going on the street ??

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1989 CRX Si
"Budget under cover"

jasonb

02-06-2003, 05:44 AM

Originally posted by HiRcc#21:
I have done alot of dyno testing different exhausts over the last 2 years and here is what we found:
on my ita crx, we found a reading of over 120hp (year old .020 over bottom end) at the wheels with this set up:
Using a new Landspeed Racing Powercore header, and a Magnaflow muffler (part# 10425). 2-1/4 in and out, 18" can.
If you measure from the flange of the header back 3" and install the muffler (edge of the can)into a 2-1/4" pipe,(with a rotateable flange and stock springs for hardware-like Lee suggested) the DB's ran at Nelson in Oct.'02 was 87. Lots of top end and it didn't hurt the bottom end either.
The straight pipe ends 7 inches after the linkage. (measured from the attachment point of the shifter to shift linkage arm.)We welded on a piece of round stock and bent it to the similar specs of a factory pipe, and used the rubber hangers to the factory "hooks" on the tub, and it works fine. No vibrations in the seat at full song.
We built approx. 15 different styles to arrive at this one.
The header, just released, gave us 2 hp over the old DC 4-2-1 with no header wrap.
Hope this helps you out... It does work!

Very helpful post, thanks alot! So you like the Landspeed header? I havent heard much about it other than it is competitively priced and I think Import Tuner got like 7whp out of the header on a D16 motor.

Tom Blaney

02-06-2003, 12:45 PM

Great information and great timing. I have been running my crx/si with a header from opm (I think) and was about to unload a dc header. Do you have any performance differences with those. the opm is a 4 into 1 and the dc is sorta a 4/2 into 1. the same tube length and dia. for both headers just a little different shape.

Tom

HiRcc#21

02-07-2003, 12:09 AM

Fleetcare, Jason B, and Tom Blaney-
Fleet- to answer your question first....
as for proving it won't be streetable...
I dealt with one shop for the last few years, and they know nothing about import performance if it isn't a catalog, so when I went to them, I kept buying material and got a good raport build with them, after while, they just did what I wanted with out any hassles...
Jason B-Yes, I like the Landspeed design, it is the best I have found so far, and they are willing to allow my input into the final design...from dyno testing here in Ohio..so that was a deal I set up, cause I wanted the flexibility to send the header back if I found more HP by tunning the header to my needs....so, the design is final now, and it does pick up about 7 overall, but you have to really have cold air to get the most of it, so the avg. we got in summer heat was 2 hp, plus Todd@Landspeed was super easy to deal with and very helpful in the developement process....
Tom Blaney-
As for the differences between the Landspeed header and the OPM is quite vast...
I know who builds the OPM header, and I know who Tom is using for motor work (SunBelt Performance in Atlanta), so his header was developed (I think, not sure, but a good guess here), using the head he runs from Jim @ Sunbelt and Toms R & D over the years...
I approached the Landspeed guys due to a recommendation from Johnathan Speigel at Progress Technologies (suspension co.), and Johnathan got me hooked up with the Magnaflow muffler, and with Todd @ Landspeed.
I set out to get a header set up for the civic/crx similar to how Tom did his deal with his header builder...Except I use Dan Paramore Racing Engines in Gardena, Ca.. I picked up a ton of hp with Dan and thus felt that I needed to upgrade my header since it was 5 years old. So the Landspeed guys worked with me to get a "tune" that sang to me so to speak..so that is how I did it. I just did basic R & D on the dyno with different exhaust lengths till I found the magic spots and then built a final product.

***Sorry this was so long, but I wanted to address each one of you guys individually with your paticular needs.
I hope this info helps, and it shortens your learning curve and saves you some bones.

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http://www.Street-N-Track Autosports- owner
ITA CRX Si #21
Central Division SCCA

LTBMotorsports

02-07-2003, 12:21 PM

The header sold by OPM is designed for all IT cars not specifically for a certain head or Sunbelt Engines, that header is made by Walt Pucket out of NC. and you can purchase it from my company ( LTB Motorsports ) or from OPM.

This is my 3rd header from Walt that I used in my own cars ( 2 for CRX and 1 for my Delsol ) and they are great headers and I would recommend it to any IT car.

Louis B.

HiRcc#21

02-07-2003, 01:48 PM

Louis-
Thanks for answering the question I put in my post. I was under the impression from talking to Tom a few years ago, that his header was more specificly built for Toms D16A6 config. in his CRX. But I could be mistaken that Walt's is more of a general fittment that suits all Honda's rather than just the crx..
I have heard they work pretty well, I know Tom won the ARRC with one, and I hope you didn't think that I was putting the OPM header down. I just replied to the posts that were addressed to me....

BTW- can you supply us with dyno sheets or how you install your whole exhaust like I did? It would be neat to see how you have your exhaust built, and what kind of HP no. you have....If I wanted to buy an OPM header, I would want to know this info first.

------------------
http://www.Street-N-Track Autosports- owner
ITA CRX Si #21
Central Division SCCA

jasonb

02-07-2003, 03:15 PM

Originally posted by HiRcc#21:
BTW- can you supply us with dyno sheets or how you install your whole exhaust like I did? It would be neat to see how you have your exhaust built, and what kind of HP no. you have....If I wanted to buy an OPM header, I would want to know this info first.

I would love to know the same. If there isnt a huge difference between the setup that HiRcc has vs. a setup with Walt's header, I'd much rather save the the couple hundred dollars and go with the Landspeed.

HiRcc, do you have a dyno chart of the setup you listed above?

LTBMotorsports

02-07-2003, 04:40 PM

I will post an updates Dyno sheet within the next few weeks after I take the car to the Dyno, I am working on the suspension now and Walt just send me last week my new Delsol Header.
As for the CRX I don't have the Dyno info anymore since I sold the car to David White but if I remember correctly the Pucket header showed 118 hp at the Dyno comparing to the DC 4/1 header with only 115.5
The way I setup the pipe on the CRX was using 2.5'' pipe and using a Dynomax 2.5'' muffler ( about $40 from Summit ), on the new Delsol I am using a Borla Race muffler and a 2.5'' pipe.

Also the location of the muffler is very important when I was installing mine we called Walt Pucket and he told me exactly where to weld the muffler based on the pipe length and the location of the down pipe on the header, also I am sure if he build you a header we can get that info from him.

Louis

CRX Lee G

02-08-2003, 12:29 PM

I've owned two OPM 4-1 headers by Walt. The first was on an ITA car and I always thought that it was one of the performance pluses that I had over the DC 4-2-1 guys. Becasue of this, I had them make a header for my EP/FP '88 CRX. I gave Walt my specifics on power and rev expectations and he did the math coming with up with a header similar to but with some different lengths than the ITA one. I am not familiar with the Landspeed products, I think they are newer to the business than when I bought my last race header.

I had an ITA car with a 4-1 Kamikaze stainless header and I think it was rather restrictive like a olympic sprinter with beans in his nose. I think it was mostly flashy kid stuff.

SMSP

02-08-2003, 10:23 PM

http://www.imagestation.com/picture/sraid4...57/fce624a6.jpg (http://www.imagestation.com/picture/sraid43/p62f3cd7aae7b2e59f892854bf9304957/fce624a6.jpg)

jasonb

02-09-2003, 02:33 AM

Originally posted by SMSP:
http://www.imagestation.com/picture/sraid43/p62f3cd7aae7b2e59f892854bf9304957/fce 624a6.jpg://http://www.imagestation.com/picture...7/fce 624a6.jpg (http://www.imagestation.com/picture/sraid43/p62f3cd7aae7b2e59f892854bf9304957/fce624a6.jpg)

I take it this is one of your headers? I emailed you a couple days ago regarding a header for an ITA CRX. Still waiting for a response.

HiRcc#21

02-09-2003, 09:57 PM

Jason B-
sorry to take a couple days to reply, was out of town on business.
the dyno sheet you need, i no longer have. I wiped it out of my dyno in the spring. I have quite a few cars come through on my dyno, and didn't save the info. I know of someone else who might though, he runs the same set up I do:header and all.
Let me call him on Monday, and see if he has a sheet....He did all his dynowork on the dyno @ Magnaflow when they were messing around with a proper can length and such before making the final product....
I will update as soon as I get a hold of him...

HiRcc#21

02-11-2003, 02:51 PM

Jason B-
I talked to my buddy with the dyno sheets. He said his dyno sheets are not for the Landspeed header. They are with the OPM header and the DC 4-2-1 and the DC 4-1.
He said that he found he lost 5 hp when he used the 4-1 with a long intake system (ex. iceman). He found that the short intake made better power with the DC 4-2-1 unit. So depending on if you have the factory air box (consider this a short intake system), or the iceman as a short set up, you need the 4-2-1 DC, or the OPM header with a short intake. The AEM cold air doesn't work as well with the OPM or the DC 4-1 header.
So depending on your header, this should help you decide on an intake/header set up.
The primary tubes have to be at least 1 5/8's or larger to work with the D16A6 config...He is going to fax me the dyno sheets today or tommorrow he said.
If you give me your email addy, I will scan them in and email them to you.
He hasn't been to the dyno with the Landspeed header yet, but I know when we went from the old 4-2-1 DC unit to the landspeed (using the short iceman set up) we picked up more hp. than with any of the other header/intake configurations.
I hope this helps you...

[This message has been edited by HiRcc#21 (edited February 11, 2003).]

jasonb

02-11-2003, 03:18 PM

Originally posted by HiRcc#21:
Jason B-
I talked to my buddy with the dyno sheets. He said his dyno sheets are not for the Landspeed header. They are with the OPM header and the DC 4-2-1 and the 4-1.
He said that he found he lost 5 hp when he used the 4-1 with a long intake system (ex. iceman). He found that the long intake made better power with a short intake and the DC 4-2-1 unit. The primary tubes have to be at least 1 5/8's or larger to work with the D16A6 config...He is going to fax me the dyno sheets today or tommorrow he said.
If you give me your email addy, I will scan them in and email them to you.
He hasn't been to the dyno with the Landspeed header yet, but I know when we went from the old 4-2-1 DC unit to the landspeed (using the short iceman set up) we picked up more hp.
I hope this helps you...

Chris, I bet it Bernardo that you spoke with about this huh? I spoke with him not long ago about this and he said everything that you just said. I remeber looking at his dyno charts back when he came up here for a race at Sears point. With his setup, including a stock bottom end, he made around 124whp and 110wtq. Pretty impressive.

HiRcc#21

02-11-2003, 03:32 PM

Jason B-
yes it is Bernardo. He and I are running the same set up. Our motor builder, Dan Paramore put Bernardo and I together in order to do some West Coast vs. East Coast testing with his cylinder heads and such.
Bernardo will be getting a Landspeed header very soon, and then he said he would dyno it and let us all in on the test info he gets.
He does run a pure stock bottom end, and Dan's cylinder head. I know at one race at Willow last year, a few skeptics were pointing fingers at Bernardo for an illegal engine. Well he blew up the one motor, then swapped in a purely stock motor with the same head and won the next weekend. That silenced the skeptics...that was impressive to me.
So I guess we will have to wait and see what results he puts out, when he gets a Landspeed header on there. He is more proven in the ranks than I am, so I will let his no.
s speak, since you know of him and you have seen his previous dyno sheets.
All that is left is get Dan to do a head for you I guess....lol

davew

02-11-2003, 03:43 PM

<font face="Verdana, Arial" size="2"> With his setup, including a stock bottom end, he made around 124whp and 110wtq. Pretty impressive. </font>

I'd agree is this was a drag race forum. but peak numbers are pretty useless for roadracing, and a terrible way to compare headers. I'd gladly give up a handfull of peak hp for more power out of the turns (on most tracks). Its sorta like saying your wife gained 10 lbs...well, it makes a huge difference if this was in the top or the bottom end (to some).

dave w

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