Dtsnlvrs Posted December 17, 2007 Share Posted December 17, 2007 Sin City Z Dyno Day aka how using a dyno to select weber jets makes a difference. We had a dyno day on the 16th and I used it as an opportunity to fine tune my jetting, boy was I way off (Lean). First off, we will not discuss the particulars of my engine, I know I could have done things differently. The point here is to show the importance of dyno tuning....even after three pulls I feel I should change a few more things. Initial Pull RunFile_001.drf: 52.68 °F 28.00 in-Hg Humidity: 18 % STD: 1.05 Average Gear Ratio: 60.59 Second pull after going up (larger) one size on the mains RunFile_002.drf: 53.86 °F 28.00 in-Hg Humidity: 17 % STD: 1.05 Average Gear Ratio: 60.59 Third pull after going down (smaller) two sizes on the air correctors RunFile_003.drf: 54.56 °F 27.99 in-Hg Humidity: 15 % STD: 1.05 Average Gear Ratio: 60.57 Quote Link to comment Share on other sites More sharing options...
1 fast z Posted December 17, 2007 Share Posted December 17, 2007 Did you ever have a wide band on it before dyno tuning? Quote Link to comment Share on other sites More sharing options...
Dtsnlvrs Posted December 17, 2007 Author Share Posted December 17, 2007 http://youtube.com/watch?v=KLmmG90OuoY Quote Link to comment Share on other sites More sharing options...
Dtsnlvrs Posted December 17, 2007 Author Share Posted December 17, 2007 Did you ever have a wide band on it before dyno tuning? Nope, tuned it with the plugs and the seat of my pants. Quote Link to comment Share on other sites More sharing options...
S30TRBO Posted December 17, 2007 Share Posted December 17, 2007 Looking good Buck!! Quote Link to comment Share on other sites More sharing options...
Dtsnlvrs Posted December 17, 2007 Author Share Posted December 17, 2007 Hey Joe, I am thinking I should drop to a 1mm head gasket, reconfirm my cam timing, and then play with the ignition curve. Right now the timing is 32deg all in. I may bump it to 36deg. Also, might try the 33mm chokes again and use the wideband and the dyno to get it right this time. Quote Link to comment Share on other sites More sharing options...
Evan Purple240zt Posted December 18, 2007 Share Posted December 18, 2007 That is a perfect example of why tuning seat of the pants is not the way to go. Nice numbers, that is great you were able to pick up some ponies. I would not own any sort of performance car without a wideband after owning one. Evan Quote Link to comment Share on other sites More sharing options...
Thumper Posted December 18, 2007 Share Posted December 18, 2007 Is it just me or does the afrs look alittle lean. I've always thought 13:1 was good for n/a engines and thus tuned my engine for it. Seat of the pants feels faster with 13:1 then 13.5:1 for me. So you might have some more power if you richen it up alittle more. Quote Link to comment Share on other sites More sharing options...
Dtsnlvrs Posted December 18, 2007 Author Share Posted December 18, 2007 Is it just me or does the afrs look alittle lean. I've always thought 13:1 was good for n/a engines and thus tuned my engine for it. Seat of the pants feels faster with 13:1 then 13.5:1 for me. So you might have some more power if you richen it up alittle more. I would agree, however there were 15 cars trying to dyno that day and I did not want to hog up more time. On a side not, the current jetting will probably be spot on come spring around here. Quote Link to comment Share on other sites More sharing options...
Tony D Posted December 18, 2007 Share Posted December 18, 2007 On a side note, the current jetting will probably be spot on come spring around here. E F I Nice numbers, that is a strong car. I always liked the 'sharpie on the sheet' look to a Weber Dyno Curve. Not the jaggies found on some EFI systems. Then again, they don't vary with the season. Give sumpthin', get sumpthin'! Quote Link to comment Share on other sites More sharing options...
Thumper Posted December 18, 2007 Share Posted December 18, 2007 I would agree, however there were 15 cars trying to dyno that day and I did not want to hog up more time. On a side not, the current jetting will probably be spot on come spring around here. K just wanted to make sure because my only Non-turbo tuning experience has been with my ls2 which is a high compression v8 vs a mid compression L6. Yepo major drawback of carbs always needs adjustment when weather changes. So you were running 32 degrees of timing on that run? I am running 35 right now on a 8.5:1 fairly stock motor with 13:1 afr's. I didn't notice in any improvements with my butt dyno with more timing and I don't think there would be. Even 35 i've heard is too much for optimal combustion. BTW nice tq curve. 3500-6000 nice and broad Quote Link to comment Share on other sites More sharing options...
Thumper Posted December 18, 2007 Share Posted December 18, 2007 E F I Nice numbers, that is a strong car. I always liked the 'sharpie on the sheet' look to a Weber Dyno Curve. Not the jaggies found on some EFI systems. Then again, they don't vary with the season. Give sumpthin', get sumpthin'! Yepo carbs are alot smoother on the dyno but I noticed that smoothing was set to 5 which is alot high for my taste. I prefer to have it lower say 3 so you can see the bumpiness. That way you can tell if you have too much timing before you can hear it. Quote Link to comment Share on other sites More sharing options...
sonomaz Posted December 18, 2007 Share Posted December 18, 2007 I'm sitting here on the couch watching clash of the choirs and selectied the link to your dyno run and I think you are in the running to win, so what number are we suposed to text? Seriously, I just love the sound of that straight six through a free flowing exhaust. So cool when you hit top gear and that note just slowly rises to that wail of "this is it! this is my best effort!!!" Awsome, dude. Paul Quote Link to comment Share on other sites More sharing options...
Dtsnlvrs Posted December 18, 2007 Author Share Posted December 18, 2007 So you were running 32 degrees of timing on that run? I am running 35 right now on a 8.5:1 fairly stock motor with 13:1 afr's. I didn't notice in any improvements with my butt dyno with more timing and I don't think there would be. Even 35 i've heard is too much for optimal combustion. BTW nice tq curve. 3500-6000 nice and broad On a stock cammed ITS car, we got our best numbers at 32deg, however, the VARA Cprod cars are running not much more cam than what I have now, and getting better numbers with 36deg. Quote Link to comment Share on other sites More sharing options...
Dtsnlvrs Posted December 18, 2007 Author Share Posted December 18, 2007 I'm sitting here on the couch watching clash of the choirs and selectied the link to your dyno run and I think you are in the running to win, so what number are we suposed to text? Seriously, I just love the sound of that straight six through a free flowing exhaust. So cool when you hit top gear and that note just slowly rises to that wail of "this is it! this is my best effort!!!" Awsome, dude. Paul Thanks Paul Quote Link to comment Share on other sites More sharing options...
S30TRBO Posted December 18, 2007 Share Posted December 18, 2007 Hey Joe, I am thinking I should drop to a 1mm head gasket, reconfirm my cam timing, and then play with the ignition curve. Right now the timing is 32deg all in. I may bump it to 36deg. Also, might try the 33mm chokes again and use the wideband and the dyno to get it right this time. 1mm, keep the timing at 32deg and try the 33mm chokes. You need to spend some good loving on a dyno to get it right. I am just throwing this out there for good measure: Quote Link to comment Share on other sites More sharing options...
Tony D Posted December 20, 2007 Share Posted December 20, 2007 Yepo carbs are alot smoother on the dyno but I noticed that smoothing was set to 5 which is alot high for my taste. I prefer to have it lower say 3 so you can see the bumpiness. That way you can tell if you have too much timing before you can hear it. You mean on the Dyno Setting, right? That is a very good point. I was making mention since we ran the same settings when we dynoed our Bonneville Engine and with the same settings you could see more 'bumpieness' than with the Webers. But that is a very good point, many people don't ask about the smooting and interpolation settings of the dyno, and don't really see what their car is doing during tuning. Keep it fast-responding while tuning, and "Just up the smoothing for the final run you post on the internet" LOL:icon45: Quote Link to comment Share on other sites More sharing options...
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