| Author |
Message |
Ken (Allyn)
Member
Username: Allyn
Post Number: 918
Registered: 10-2001
| | Posted on Friday, May 23, 2003 - 3:33 pm: | |
No, I didn't change the jets. I have Strombergs and as an emissions carb, they have limited (legal) adjustments although you CAN tweak it a little richer. The timing was the big thing. Europas were purposly set with too much retard to pass 1972 emissions. There is an adjustment screw on the Lucas distributor that adjusts the timing and it was already on full advance. One I reset the distributor to get more advance, the engine ran so much better. Idle went up tp 2500 (I adjusted it back to 800), it started easily, no more popping or backfire, ran cooler and my gas mileage went from 12 MPG to 24 which is what it was with the old headers. Also, I blocked off the vacuum "advance" which I had learned was actually a retard for idle; again a US emissions crap thing. |
Ben Millermon (Brainsboy)
Member
Username: Brainsboy
Post Number: 323
Registered: 5-2001
| | Posted on Friday, May 23, 2003 - 7:23 am: | |
John, I think he's talking about the timming change making the HP difference. |
John_Miles (John_miles)
Junior Member
Username: John_miles
Post Number: 76
Registered: 7-2001
| | Posted on Friday, May 23, 2003 - 1:25 am: | |
Did you change the jets, Ken? If not, and you just adjusted the idle mixture screws, how could that have any effect on HP at the top end of the tach? |
Ken (Allyn)
Member
Username: Allyn
Post Number: 904
Registered: 10-2001
| | Posted on Wednesday, May 21, 2003 - 8:59 pm: | |
BTW, you'll also see that HP gain when you adjust it right. I was pretty unimpressed with my new exhaust until I finally found the best set up. I first set the carbs a touch richer (not easy with Strombergs!) and then advanced the timing with that great little wheel Lucas has on the distributor (yes, I AM complimenting Prince Of Darkness Lucas) to just short of pinging and lo and behold, my little 117 HP Europa seemed like it had at least 125 HP! LOL But with such a tiny light car, it's a noticable difference. |
Ben Millermon (Brainsboy)
Member
Username: Brainsboy
Post Number: 319
Registered: 5-2001
| | Posted on Wednesday, May 21, 2003 - 6:29 pm: | |
Ken was right. Too Lean. I just adjust the carbs to run richer and it cured 60% of the problem. Also I adjusted the timming just a hair, and that solved the rest. Thanks guys |
John_Miles (John_miles)
Junior Member
Username: John_miles
Post Number: 73
Registered: 7-2001
| | Posted on Wednesday, May 21, 2003 - 1:06 pm: | |
Not an unusual symptom, especially with aftermarket exhausts.
You might try opening your idle mixture screws about 1/2 turn each, just as an experiment. You will tend to get more exhaust popping on the overrun when your idle mixture is too lean. I'm not sure why -- you'd think it would be the other way around -- but that's how it works. |
Ken (Allyn)
Member
Username: Allyn
Post Number: 901
Registered: 10-2001
| | Posted on Wednesday, May 21, 2003 - 1:00 pm: | |
That happened on my Lotus when I got a new SS exhaust. Popping as in backfire is TOO LEAN! Not too rich. Your exhaust system is too hot and igniting unburnt fuel. Make it richer and you'll run cooler, and no more backfire. If you have a larger diameter after market exhaust and didn't advance the timing and/or make the carbs a tad richer, you'll get this.
|
Philip Airey (Pma1010)
Junior Member
Username: Pma1010
Post Number: 250
Registered: 7-2002
| | Posted on Wednesday, May 21, 2003 - 12:42 pm: | |
Ben
I think some popping on decel through the exhaust is normal - my 77 (carbs, no cats) burbles (sounds more like a snarl with cracks and pops) through the Tubi on overrun. The previous ANSA didn't do this. I think it's all to do with back pressure in the design of the muffler. Now if it is popping and banging through the muffler on cruise, I'd opine you're likely running rich.
HTH |
Steve Magnusson (91tr)
Intermediate Member
Username: 91tr
Post Number: 1802
Registered: 1-2001
| | Posted on Wednesday, May 21, 2003 - 11:46 am: | |
Ben -- post a pic/description of the (non-stock?) carb/intake set-up you're running... |
"The Don" (Mlemus)
Advanced Member
Username: Mlemus
Post Number: 4722
Registered: 8-2002
| | Posted on Wednesday, May 21, 2003 - 11:31 am: | |
I had a similar problem on my carb 308. When the Air pump belt "fell off" it went away. |
DJParks (Djparks)
Junior Member
Username: Djparks
Post Number: 239
Registered: 2-2003
| | Posted on Wednesday, May 21, 2003 - 11:30 am: | |
Ben, Thanks
DJ |
Ben Millermon (Brainsboy)
Member
Username: Brainsboy
Post Number: 315
Registered: 5-2001
| | Posted on Wednesday, May 21, 2003 - 10:50 am: | |
Barney thanks |
Ben Millermon (Brainsboy)
Member
Username: Brainsboy
Post Number: 314
Registered: 5-2001
| | Posted on Wednesday, May 21, 2003 - 10:49 am: | |
I used the Flowmaster 80 series duel in duel out part#42582 then I went out to two 2.5" resinators. Now it has a nice deep sound at idle. Sounds more like what a v8 should sound like. Because the resinators are so big it keeps the deep v8 sound until around 2400rpm. After 2400rpm it has the Ferrari sound to it, but a little bit louder and deeper. Full throttle sounds pretty much the same, I would say it only improved the full throttle sound maybe 10%. I only tacked welded the resinators on because Im going to try out some 2" resinators this weekend, and maybe some other brands. Mostly its just trail and error, finding a sound that makes your ear happy. |
Barney Guzzo (Trinacria)
Junior Member
Username: Trinacria
Post Number: 223
Registered: 8-2002
| | Posted on Wednesday, May 21, 2003 - 10:48 am: | |
Excess unburned fuel I believe. Too rich. |
DJParks (Djparks)
Junior Member
Username: Djparks
Post Number: 238
Registered: 2-2003
| | Posted on Wednesday, May 21, 2003 - 10:30 am: | |
Ben, What is the extent of your Flowmaster coversion? (at the risk of highjacking the thread)
DJ |
Ben Millermon (Brainsboy)
Member
Username: Brainsboy
Post Number: 313
Registered: 5-2001
| | Posted on Wednesday, May 21, 2003 - 8:56 am: | |
All new exhaust. I converted to the flow master like rob did. |
Paul (Pcelenta)
Member
Username: Pcelenta
Post Number: 341
Registered: 7-2002
| | Posted on Wednesday, May 21, 2003 - 7:28 am: | |
Ben, if this just started occuring could possibly be an exhaust leak....check all your connections and exhaust donuts first... |
Ben Millermon (Brainsboy)
Member
Username: Brainsboy
Post Number: 312
Registered: 5-2001
| | Posted on Wednesday, May 21, 2003 - 7:16 am: | |
My 308 car has just a little bit of popping sound from the exhaust when I deaccelerate or do a downshift. assuming the timming is ok, Would that indicate the carbs are too learn or rich? |