Carb tuning with exhaust analyzer |
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Carb tuning with exhaust analyzer |
KaptKaos |
Mar 9 2012, 10:05 AM
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#1
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Family Group: Members Posts: 4,009 Joined: 23-April 03 From: Near Wausau Member No.: 607 Region Association: Upper MidWest |
I am planning to tune my carbs with an exhaust gas analyzer that I have access to at my weekly autoshop class. I have a 1.8 with a carb cam running dual weber 40s. I don't know the stats on the cam. I tried a few times to see if it was marked, and to measure the lift and duration, but neither was successful for a number of reasons. Regardless, it does run well, but I want to dial in the carbs better.
I will be running an SVDA dizzy, with vacuum advance. Timing at 30 degrees BTDC @ 3500, no vacuum connected. I have access to an exhaust gas analyzer at my weekly autoshop class, and I intend to use it to measure my air/fuel ratio. I have read that I want to be at about 13.5:1 to 14:1 at idle and cruise, and at about 12.5:1 at wide open throttle (wot). Does this sound about right? Any advice or tips here are appreciated. |
McMark |
Mar 9 2012, 10:10 AM
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#2
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914 Freak! Group: Retired Admin Posts: 20,179 Joined: 13-March 03 From: Grand Rapids, MI Member No.: 419 Region Association: None |
Is it the style that you can drive around with? Unloaded tuning is worthless on the road.
Your ratio numbers are pretty much right, but listen to how the car feels more than the numbers. |
KaptKaos |
Mar 9 2012, 12:07 PM
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#3
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Family Group: Members Posts: 4,009 Joined: 23-April 03 From: Near Wausau Member No.: 607 Region Association: Upper MidWest |
Unfortunately not. It's stationary.
I had done this before and it was pretty good. What else do you recommend? |
Aaron Cox |
Mar 9 2012, 12:25 PM
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#4
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Professional Lawn Dart Group: Retired Admin Posts: 24,541 Joined: 1-February 03 From: OC Member No.: 219 Region Association: Southern California |
Borrow an LM1/LM2?
Drive around/log data? |
brant |
Mar 9 2012, 12:38 PM
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#5
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914 Wizard Group: Members Posts: 11,625 Joined: 30-December 02 From: Colorado Member No.: 47 Region Association: Rocky Mountains |
it has to be underload
you either have to drive around with it or use a rolling dyno borrow an LM1 brant |
jmill |
Mar 9 2012, 12:49 PM
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#6
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Green Hornet Group: Members Posts: 2,449 Joined: 9-May 08 From: Racine, Wisconsin Member No.: 9,038 Region Association: Upper MidWest |
I have one of these. Works great. You can find them on Ebay once in a while for about $150. There's one there now for way too much and even one on craigslist.
Heathkit EGA Attached image(s) |
KaptKaos |
Mar 9 2012, 01:18 PM
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#7
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Family Group: Members Posts: 4,009 Joined: 23-April 03 From: Near Wausau Member No.: 607 Region Association: Upper MidWest |
Borrow an LM1/LM2? Drive around/log data? Who the f__ are you? (IMG:style_emoticons/default/chair.gif) |
Elliot Cannon |
Mar 9 2012, 02:46 PM
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#8
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914 Guru Group: Retired Members Posts: 8,487 Joined: 29-December 06 From: Paso Robles Ca. (Central coast) Member No.: 7,407 Region Association: None |
(IMG:style_emoticons/default/agree.gif) (IMG:style_emoticons/default/WTF.gif) Or welcome back? (IMG:style_emoticons/default/confused24.gif)
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Aaron Cox |
Mar 9 2012, 02:55 PM
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#9
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Professional Lawn Dart Group: Retired Admin Posts: 24,541 Joined: 1-February 03 From: OC Member No.: 219 Region Association: Southern California |
(IMG:style_emoticons/default/agree.gif) (IMG:style_emoticons/default/WTF.gif) Or welcome back? (IMG:style_emoticons/default/confused24.gif) Joo meees me? lol... |
carr914 |
Mar 9 2012, 03:23 PM
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#10
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Racer from Birth Group: Members Posts: 118,695 Joined: 2-February 04 From: Tampa,FL Member No.: 1,623 Region Association: South East States |
Borrow an LM1/LM2? Drive around/log data? Who the f__ are you? (IMG:style_emoticons/default/chair.gif) (IMG:style_emoticons/default/agree.gif) |
KaptKaos |
Mar 9 2012, 04:12 PM
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#11
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Family Group: Members Posts: 4,009 Joined: 23-April 03 From: Near Wausau Member No.: 607 Region Association: Upper MidWest |
(IMG:style_emoticons/default/agree.gif) (IMG:style_emoticons/default/WTF.gif) Or welcome back? (IMG:style_emoticons/default/confused24.gif) Joo meees me? lol... Of course I did. How them brakes coming? BTW: what was the deal with that guys comment on your brake picture? Out of line much? Geez.... |
Aaron Cox |
Mar 9 2012, 04:17 PM
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#12
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Professional Lawn Dart Group: Retired Admin Posts: 24,541 Joined: 1-February 03 From: OC Member No.: 219 Region Association: Southern California |
(IMG:style_emoticons/default/agree.gif) (IMG:style_emoticons/default/WTF.gif) Or welcome back? (IMG:style_emoticons/default/confused24.gif) Joo meees me? lol... Of course I did. How them brakes coming? BTW: what was the deal with that guys comment on your brake picture? Out of line much? Geez.... Not to threadjack.. but brake project is in progress. Studying for a final this weekend, so postponed a week. Guy is a college buddy. NBD - nuked it! Call me later. |
Elliot Cannon |
Mar 10 2012, 01:29 AM
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#13
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914 Guru Group: Retired Members Posts: 8,487 Joined: 29-December 06 From: Paso Robles Ca. (Central coast) Member No.: 7,407 Region Association: None |
So, this is what? Your seventh year of college?
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nsr-jamie |
Mar 10 2012, 06:17 AM
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#14
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914 guy in Japan Group: Members Posts: 1,182 Joined: 7-November 07 From: Nagoya, Japan Member No.: 8,305 Region Association: None |
I had my car set up this way last year around october or so and it made a big difference..my car was actually running lean. I am running duel 40mm Dellortors. I had my local shop do it for me, they only charged me like 45 dollars which I think was too cheap and I helped out a bit...they attach it to the car and take it out on the roads for a while and make measurements and than set the carbs.
Some pictures (IMG:http://www.914world.com/bbs2/uploads_offsite/www.dreamgate.ne.jp-8305-1331381822.1.jpg) Before setting (IMG:http://www.914world.com/bbs2/uploads_offsite/www.dreamgate.ne.jp-8305-1331381823.2.jpg) carbs apart (IMG:http://www.914world.com/bbs2/uploads_offsite/www.dreamgate.ne.jp-8305-1331381825.3.jpg) after setting and another test run (IMG:http://www.914world.com/bbs2/uploads_offsite/www.dreamgate.ne.jp-8305-1331381827.4.jpg) |
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