Went out to the track with my 426 Jeep to test the Modern Muscle 85mm throttle body. After installing it on my stock 300c I immediately noticed far more throttle response. I thought it was time to track test it at Irwindale and see if it could out perform the 90mm that has been on my Jeep for some time. I made three passes, two with the Arrington 90mm and a third pass with the smaller 85mm based on the factory throttle body. :surprise: I picked up 2/100's and went from two back to back 88.76mph(with the 90mm) to a 89.03 with the 85mm. Not a HUGE difference forward but DEFINETLY NOT a step backwards! All with a CNC ported OEM throttle body. Interesting results.:whistle:
Hey Steve hows the tranny holding up? How does the stock T/BODY stack up against these 2 in ET & MPH.
Steve, did you see any change in AF between the two? You didn't change any tuning between the two? I wonder if the smaller TB richened you up just a hair... Thoughts?
Welp, major browny points for trying. But IMO 2/100's doesn't make for any comparison. Two reasons, changing out the TB allowed additional cool down period and also this occured later in the evening which most likely lead to a lower DA as well. I wish you'd had time to do one more back to back run, that would have helped.
It went fatter. No.......I did them all between 5:00 and 6:30 in the 90 degree heat and have the burns and cuts on my hands to prove it. I didnt check it but trust me the DA didnt drop 2000' to make that kind of difference Like I said..........it didnt slow it down!!!
Well I can't give you exact DA's for Irvine, but I can give you the DA for California Speedway. At 5:00pm it was +3343 and at 6:30 3075. So just an example at 5:00pm: The closest weather results for 10/02/2008 at 05:01 pm Time recorded 4:53 PM Temperature °F 84.9 Dew Point °F 48.9 Altimeter Setting 29.78 Inches Mercury Absolute Pressure: 28.6 Inches Density Altitude: 3343.3 feet Track Elelvation: 1121 feet UnCorrected ET: 12.00 (sec) @ 115 (MPH) Corrected ET to Sea Level: 11.514 (sec) @ 119.934 (MPH) And at 6:30: The closest weather results for 10/02/2008 at 06:30 pm Time recorded 6:53 PM Temperature °F 80.1 Dew Point °F 55.0 Altimeter Setting 29.79 Inches Mercury Absolute Pressure: 28.61 Inches Density Altitude: 3075.2 feet Track Elelvation: 1121 feet UnCorrected ET: 12.00 (sec) @ 115 (MPH) Corrected ET to Sea Level: 11.556 (sec) @ 119.503 (MPH) So just lowering the DA by 300ft results in a 4/100ths difference. Ya I know we're splitting hairs :whistle:.......................... but that's exactly it, WE'RE SPLITTING HAIRS :bigwink:
Wow. I'm just simply amazed at how you guys know all this stuff. I wouldn't even begin to be able to sort through all that information!!! You guys are obsessed!!! lol. In a good way!!! But you do make stupid guys like me feel incompetent...... Chase
oK SO WHO WANTS TO TRADE MY MY ARRINGTON UNIT FOR A 85MM ONE??? Steve did you notice that the 85mm is better for daily driving?
This morning I cold started it and no surging up and down drama. Fires up and idles like stock. Driveability is much better. Dont get me wrong I like the 90mm but you dont need it for a 5.7/6.1. Another way to part us with money. A 90mm is like putting a 1100cfm Dominator on a small block street car when it will throttle and perform better with an 850cfm with vacuum secondaries.
How well would the 85mm work on a stock manifold I see yours is ported does it bolt right up or is there any fab work that has to be done on a stock setup?
Here Cam..... Iwrindale not Irvine. Here is the weather for yesterday....... http://www.wunderground.com/weatherstation/WXDailyHistory.asp?ID=KCADUART2&month=10&day=2&year=2008 Irwindale with a 350' track elevation.......At 5:00pm it was approx 2433'.......at 6:30 it was approx 2108'.......hardly enough to matter but none the less just general information that is interesting. Again.....I would have expected the 4890lb Jeep to slow down...or see no gain...evidently more/bigger is not always better and possibly air speed is more important than just a big hole.
Actually I installed in on my 300SRT8 and "noticed" immediate improvement in throttle response. I have no way to back it up but my "butt-o-meter. Let's see $420 for 85mm vs $980 for 90mm....hhhhmmm
Not enough data for confirmation of results. The level of repeatablility are by chance. In reasearch terms in order for something to be clinically significat it must have a P value of less than 0.05 which basically means that its very unlikely to have happened by chance. 1 run is a good start, but I wouldn't start trading in 90mm TBs based on it. Thanks for the data - without guys like you we wouldn't be anywhere near where we are now.. Thanks again. JT
I might mess around with testing this stuff at out November track rental. Do something like this: 90mm 85mm 85mm 90mm 90mm 85mm 90mm LOL, that should be fun keeping up with.
Well to me, it did slow down. You gained 2/100's but should have gained 4/100's just to break even. Mind you, in a perfect world. And I completely disagree with you about a larger TB not being needed. I have far to much proof it does work when everything else is in order for the requirement. But for your average Joe just to bolt it on and expect some gains, not gonna happen.
Agree to Disagree Cam we agree to disagree......My recent points are based on dyno pulls conducted just last week before the track....and two track events in the last 6 days .....alot of "consistent" track time....I log and run and log. As an example, I have been running around with less horsepower at the wheels for a good year, from a manifold done by a local SoCal guy who at the time I thought he knew what he was doing. The "guy" hand ported and opened up the bellmouth only to lose velocity and 18 horsepower and 18ftlbs throughout the curve. You and I can drive down to Harmanmotive and review this real world data. Not to reveal too much but three seperate engine builders.....one on this site has seen the same results manifold wise that I have seen. All four of us cant be wrong. After installing a "SMALLER" ported manifold we picked up those hp/tq losses.....that is why I can propel a "daily driver" 5,000lb vehicle in a DA of 2400' to 12.1....consistently time after time. Not to argue but I have owned a few engines larger than this little 426. The difference is I dont have a simple distributor or carburetor and engine dyno to dial it in until I get to the track. Now we deal with fuel injection, sensors, etc which is not dependent like a carburetor on vacuum signal and atmospheric pressures across throttle bore venturis. I respect your view but again I disagree with you based on hard dyno sheets and track times, all relevant documentation. This carburetor sizing formula has been around for ages. It is still close for fuel injection....... STREET CARB. CFM = RPM X DISPLACEMENT ÷ 3456 X .85 RACING CARB. CFM = RPM X DISPLACEMENT ÷ 3456 X 1.10 Max cfm for a 100% volumetric efficient "race" 426 at 6200.....840cfm is max it will pull. So why do i need to plug a 1000cfm hole in the front of it? Another site that may help those of us from chasing some thing that doesnt exist because mathematically it cant http://www.csgnetwork.com/cfmcalc.html Dont worry......we can still hang out! lol!!!!