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#1
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New HPI SpeedMaster Heads on the Dragster
We're going to put a set of as cast SpeedMaster heads on the dragster to test. Question? The headers I have for the round port heads have the Borla Mufflers pictured on them. I've heard you lose around 30HP with these. Is that true? If that's the case I might swap to open collectors because my old d-port set up ran open collectors and the heads are the only thing I'm going to change.
I will calculate the reduced weight into the ET. Thoughts?
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Randy Repp 1964 GTO "GoatZilla" 1964 GTO "Injunuity" A/FX Nostalgia Super Stock 220" Rear Engine Pontiac Powered Dragster https://www.facebook.com/PontiacSpeedShop/ https://www.facebook.com/GoatZillaRacing/ https://www.facebook.com/groups/RebuildExcitement/ https://www.facebook.com/Call1844RacersRV/ https://www.facebook.com/groups/INJUNWARS/ |
#2
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My question is why would you run mufflers, of any kind, on a drag racer, unless it was a track or class rule, for some reason ?
I've always run collector extensions on my door cars, but not mufflers. |
#3
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Because the headers I have, also have the Borla mufflers instead of an open collector.
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Randy Repp 1964 GTO "GoatZilla" 1964 GTO "Injunuity" A/FX Nostalgia Super Stock 220" Rear Engine Pontiac Powered Dragster https://www.facebook.com/PontiacSpeedShop/ https://www.facebook.com/GoatZillaRacing/ https://www.facebook.com/groups/RebuildExcitement/ https://www.facebook.com/Call1844RacersRV/ https://www.facebook.com/groups/INJUNWARS/ |
#4
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I run mufflers all the time on my car with a X-pipe. Only car in Nostalgia Super Stock with mufflers. My exhaust set-up weighs 65lbs. Car runs quicker with mufflers than open headers or collector extensions. Plus its neat to spot a few Hemi's with open headers and run them do.
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66 GTO Nostalgia Super Stock/Street Legal Car 421 CID, stock block, Wenzler Intake, 2- Carter 750 AFB's, 3.90 Gears, Full Factory Interior, Full Exhaust, Stock Suspension 3750LBS 9.77@136.99 Multiple NSCA/NMCA World Champion 66 GTO 389 3x2, 4 speed, 4.33 gear, Montero Red 33K original Miles 67 GTO 2dr Post, 428, Tri Power, 3.55 Gears 80 Trans Am Black SE Y84 W72 WS6 |
#5
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Because I'm old and I don't like loud noises.
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Less said,,,,,,,, Less mended. |
#6
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"...Car runs quicker with mufflers than open headers or collector extensions..."
WOW ! Never heard of that before. But, I suppose that the extra back pressure MIGHT help certain combos. So, do any of the quickest NHRA Stock & SS racers run a complete exhaust system, so that they can run a little quicker ??? There may be some, or lots of 'em. I have no way of knowing. "...the headers I have, also have the Borla mufflers instead of an open collector...I've heard you lose around 30HP with these. Is that true? If that's the case I might swap to open collectors..." So, if you think those muffs knock off 30hp, or even a smaller amount, then what is the reason for not removing them ? Until now, the only race cars I've read about using muffs are some circle track cars, in order to reduce the sound to those who live close to the track. I suppose there might be some drag strips that do the same, tho I have personally never read of any. Running muffs on drag cars to improve ET is just a concept I'm not familiar with. But then, I suppose there are LOTS of things I never heard of. Last edited by ponyakr; 04-26-2019 at 02:29 PM. |
#7
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Randy, are the Borla mufflers straight through design? If so I highly doubt they will cost you 30 HP.
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Less said,,,,,,,, Less mended. |
#8
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Quote:
There will be a Super Stock car out next year that will have mufflers on it, along with a license plate, stock suspension and a 9" tire. Not sure how long it has been since you have raced but there a allot of fast cars running mufflers. Muffler Technology has come along way in the last 15 years.
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66 GTO Nostalgia Super Stock/Street Legal Car 421 CID, stock block, Wenzler Intake, 2- Carter 750 AFB's, 3.90 Gears, Full Factory Interior, Full Exhaust, Stock Suspension 3750LBS 9.77@136.99 Multiple NSCA/NMCA World Champion 66 GTO 389 3x2, 4 speed, 4.33 gear, Montero Red 33K original Miles 67 GTO 2dr Post, 428, Tri Power, 3.55 Gears 80 Trans Am Black SE Y84 W72 WS6 |
#9
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"... there a allot of fast cars running mufflers. Muffler Technology has come along way in the last 15 years."
https://www.google.com/search?q=best...hrome&ie=UTF-8 |
#10
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Not trying to hijack the thread but I ran mufflers on my car at the track because I loved it when my little streetcar beat up on race cars. A friend of mine swore up-and-down he could hear my foot hit the floor when the light turned green Lol
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#11
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Regardless of the pro and con on mufflers, I'd vote for open collectors so it's a more accurate comparison to the other head setup.
Eric
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"Everybody has a plan until they get punched in the mouth" noted philosopher Mike Tyson Life begins at the end of your comfort zone. “The mind, once stretched by a new idea, never returns to its original dimensions.” |
#12
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Good job guys on bring an cost effective product to the market.
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#13
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Quote:
GT. |
#14
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I'm not running them brother. They look promising but not by me.
I run stuff but it will be deleted shortly so I won't waste my time here. |
#15
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Is the increase in performance not from backpressure but better cylinder scavenging?
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#16
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So you can hear the other car. I was running against a slower car, as I was running him down, he heard my womp womp with the go pedal, he hit it hard and gave me the stripe.
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Dave Polichena |
#17
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Better for them to look for you then to hear you coming.
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66 GTO Nostalgia Super Stock/Street Legal Car 421 CID, stock block, Wenzler Intake, 2- Carter 750 AFB's, 3.90 Gears, Full Factory Interior, Full Exhaust, Stock Suspension 3750LBS 9.77@136.99 Multiple NSCA/NMCA World Champion 66 GTO 389 3x2, 4 speed, 4.33 gear, Montero Red 33K original Miles 67 GTO 2dr Post, 428, Tri Power, 3.55 Gears 80 Trans Am Black SE Y84 W72 WS6 |
#18
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Oh he was looking, didn't get close to him till the 1000' mark. Hit it a few times after and he parked it...
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Dave Polichena |
#19
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how much do you hold?
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1969 carousel red firebird 455, richmond 5 speed 1964 540 gto 1971 lemans sport convertible 1972 Maverick under slow construction |
#20
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I always adjust my rear view and side mirrors to see them coming when racing a very fast car depending on which lane they are in. Not unusual for fast cars to blow their tires off when they wait so long. Gotta make sure you do not brake out and lift or tap the brakes.
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