Horsepower limits with 2.125" hemi TTI headers & 3" exhaust
#2495194
05/12/18 05:58 PM
05/12/18 05:58 PM
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Joined: Oct 2007
Posts: 1,070 Big Western Pencilveinya
Uncle Barry
OP
super stock
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OP
super stock
Joined: Oct 2007
Posts: 1,070
Big Western Pencilveinya
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What's the limits of this set up I have on my car? Just curious. It has 17793 dynomax mufflers also. My car has been 10.97 @ 122 with this and the car is going to get a rollbar put in it soon. Just looking ahead as I may want to chase this thing closer to the 9s but would like to keep this exhaust because it's a true driver. Thanks for any insights.
Last edited by Uncle Barry; 05/12/18 06:02 PM.
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Re: Horsepower limits with 2.125" hemi TTI headers & 3" exhaust
[Re: Uncle Barry]
#2495222
05/12/18 07:46 PM
05/12/18 07:46 PM
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Joined: Oct 2007
Posts: 4,209 New York
polyspheric
master
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master
Joined: Oct 2007
Posts: 4,209
New York
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There isn't an actual limit. You're already at the point where the ID is a slight restriction. It will cost more pumping loss, but also stop reverting at a lower RPM (slight bonus). How big (volume) are the mufflers? Even in 3" the case should be wide and long.
Boffin Emeritus
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Re: Horsepower limits with 2.125" hemi TTI headers & 3" exhaust
[Re: Uncle Barry]
#2495239
05/12/18 08:28 PM
05/12/18 08:28 PM
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Joined: Jan 2003
Posts: 12,171 Benton, IL.
DaveRS23
Special needs idiot
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Special needs idiot
Joined: Jan 2003
Posts: 12,171
Benton, IL.
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When I was building my 540, I asked Indy whether I should go with 2 1/8" or 2 1/4" being primarily a street car.
They told me to always go with as big a tube as possible and as free flowing exhaust as possible because the Hemis wanted no resistance to exhaust flow.
Master, again and still
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Re: Horsepower limits with 2.125" hemi TTI headers & 3" exhaust
[Re: Uncle Barry]
#2495258
05/12/18 09:08 PM
05/12/18 09:08 PM
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Joined: Aug 2003
Posts: 43,232 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,232
Bend,OR USA
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See my post on the Hemi dyno motor tests I did last month That was not in the car but the 3.0 inch head pipes with a set of 3.0 in and out by 14 inch long straight through Ultraflows did make decent power on the DTS engine dyno I have tested my old pump gas Duster with a full three inch system on it with 14x7x3.0 in and out Magnaflow muffs mounted at the rear bumper versus removing the complete exhaust system at the track, .02 ET and .2 MPH difference in the 1/8 mile 7.01 ET at 95.2 MPH with the exhaust sytem hooked up and 6.98 ET at 95.4 MPH with no exhaust system on the car, Hooker A body fender well headers with 2.0 primary pipes and 3.5 inch collectors I think the weight was possibly part of the gain and the lack of back pressure was a small part also, not enough to remove it again though
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Horsepower limits with 2.125" hemi TTI headers & 3" exhaust
[Re: Uncle Barry]
#2495384
05/13/18 02:24 AM
05/13/18 02:24 AM
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Joined: Mar 2003
Posts: 4,848 Memphis
HemiRick
master
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master
Joined: Mar 2003
Posts: 4,848
Memphis
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If the exhaust was a restriction and you did not rejet the carb after removing it, are the results worth anything?
Take care, Rick 68 Coronet R/T 440 & 68 Charger 528 Hemi,and 5 Challengers! 6 cyl, 318, 360, 383, 451
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Re: Horsepower limits with 2.125" hemi TTI headers & 3" exhaust
[Re: Uncle Barry]
#2495471
05/13/18 12:16 PM
05/13/18 12:16 PM
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Joined: Nov 2003
Posts: 5,160 Texas
dannysbee
master
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master
Joined: Nov 2003
Posts: 5,160
Texas
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I would look at some of the faster F. A. S. T. Cars. They run low 10's high nines and are restricted to 2.5 exhaust and manifolds. I would think mufflers would be a very important part of their package. I would use what they are using in a 3" in 3" out muffler.
Getting old just means you were smarter than some and luckier than others.
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Re: Horsepower limits with 2.125" hemi TTI headers & 3" exhaust
[Re: Uncle Barry]
#2495605
05/13/18 05:43 PM
05/13/18 05:43 PM
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Joined: Jan 2008
Posts: 2,363 Cotati, CA
Dave Hall
top fuel
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top fuel
Joined: Jan 2008
Posts: 2,363
Cotati, CA
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Factory buckets LOOK so much better. I don't like the look of after market seats in a stock bodied car. Your car is very nice looking and stupid fast! If the exhaust pleases you in the fit and quiet department I would just enjoy it and don't worry about a few hundo here and there.
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Re: Horsepower limits with 2.125" hemi TTI headers & 3" exhaust
[Re: Dave Hall]
#2495625
05/13/18 06:42 PM
05/13/18 06:42 PM
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Joined: Oct 2007
Posts: 1,070 Big Western Pencilveinya
Uncle Barry
OP
super stock
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OP
super stock
Joined: Oct 2007
Posts: 1,070
Big Western Pencilveinya
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Factory buckets LOOK so much better. I don't like the look of after market seats in a stock bodied car. Your car is very nice looking and stupid fast! If the exhaust pleases you in the fit and quiet department I would just enjoy it and don't worry about a few hundo here and there. Thanks Dave! The kirkeys should look good in it. My original seats are not in good shape and I want the harness to go through the seats. That's why I went with Kirkeys. I can always put original seats back in it though.
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Re: Horsepower limits with 2.125" hemi TTI headers & 3" exhaust
[Re: Uncle Barry]
#2495854
05/14/18 10:11 AM
05/14/18 10:11 AM
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Joined: Jan 2003
Posts: 7,495 Minnesota
Hemi_Joel
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master
Joined: Jan 2003
Posts: 7,495
Minnesota
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Those headers and 3 inch pipes are fine for your current performance level, and even into the nines. But those mufflers are definitely holding you back. Switch them out for some Dynomax ultraflow SS mufflers. That is what all the F.A.S.T. cars use. They are straight through, reasonably quiet, and sound good. Then you will be good to get into the nines
[img]http://i.imgur.com/boeexFms.jpg[/img]31 Plymouth Coupe, 392 Hemi, T56 magnum RS23J71 RS27J77 RP23J71 RO23J71 WM21J8A I don't regret the things I've done. I only regret the things I didn't do. "Wise men talk because they have something to say; fools because they have to say something. ~ Plato"
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Re: Horsepower limits with 2.125" hemi TTI headers & 3" exhaust
[Re: Uncle Barry]
#2495884
05/14/18 11:35 AM
05/14/18 11:35 AM
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Joined: Jan 2003
Posts: 13,375 Marion, South Carolina [><]
an8sec70cuda
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 13,375
Marion, South Carolina [><]
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Those Dynomax Super Turbo mufflers are restrictive as he11!!!! You need to either run it uncorked or, at the very least, get some good straight through style mufflers for it! It wouldn't surprise me a bit of you dropped 3 tenths by getting rid of those super turbos.
Hemis hate mufflers...they need to breathe. Definitely more sensitive to this than a wedge motor from the testing I've done. All the "old school" hemi guys told me that when I was building my hemi 12 years ago.
My dad's '69 road runner street car w/ a 480 or so hp 440-6 in it was noticeably slower when I swapped the 3" Ultra Flows for some 3" Super Turbos. He wanted it quieter, but even he was really disappointed in the noticeable loss of power after his first test drive. I knew it as soon as I pulled out on the highway leaving the exhaust shop.
My hemi runs the best either open header or w/ a pair of 4" bullets mounted right off the back of the collector (same w/ either). Everything else I've tried has slowed it down a tenth or more.
CHIP '70 hemicuda, 575" Hemi, 727, Dana 60 '69 road runner, 440-6, 18 spline 4 speed, Dana 60 '71 Demon, 340, low gear 904, 8.75 '73 Chrysler New Yorker, 440, 727, 8.75 '90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt '06 GMC 2500HD LBZ Duramax
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Re: Horsepower limits with 2.125" hemi TTI headers & 3" exhaust
[Re: Uncle Barry]
#2495886
05/14/18 11:37 AM
05/14/18 11:37 AM
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Joined: Jan 2003
Posts: 13,375 Marion, South Carolina [><]
an8sec70cuda
I Live Here
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I Live Here
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Posts: 13,375
Marion, South Carolina [><]
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There is no difference b/t the 2.5" and 3" Dynomax Super Turbo mufflers except for the actual inlet and outlet flanges. They all neck down to the same size internally.
CHIP '70 hemicuda, 575" Hemi, 727, Dana 60 '69 road runner, 440-6, 18 spline 4 speed, Dana 60 '71 Demon, 340, low gear 904, 8.75 '73 Chrysler New Yorker, 440, 727, 8.75 '90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt '06 GMC 2500HD LBZ Duramax
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Re: Horsepower limits with 2.125" hemi TTI headers & 3" exhaust
[Re: racerx]
#2495891
05/14/18 11:42 AM
05/14/18 11:42 AM
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Joined: Jan 2003
Posts: 13,375 Marion, South Carolina [><]
an8sec70cuda
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 13,375
Marion, South Carolina [><]
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I went 9.49 on some tti 2 1/8 and 3"pipes w/two chamber flowmasters. I bet it'd be close to two tenths quicker w/ something less restrictive though. A pro stocker would probably run 7s w/ some Super Turbos on it. Does that mean super turbos are gonna work good for a 9 sec car since they went 7s on something real fast? They're still horribly restrictive.
CHIP '70 hemicuda, 575" Hemi, 727, Dana 60 '69 road runner, 440-6, 18 spline 4 speed, Dana 60 '71 Demon, 340, low gear 904, 8.75 '73 Chrysler New Yorker, 440, 727, 8.75 '90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt '06 GMC 2500HD LBZ Duramax
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