Science or Intuition? making a VW go like hell

[bugkeeper]

That is a great topic. Here are my 2 cents. Tuning dual carburetors the old fashioned way is an art. It takes skill and time to master it. Most older mechanics (50 years and older) who worked for years on Italian cars know how to do this. A friend of my father who had his own Alfa Romeo shop was that kind of a mechanic. He listened to the engine and did his magic. 10 minutes later the motor was running perfect. He used to do this by ear only. Nowadays this skill is lost, today’s mechanics don’t even know how to spell the word carburettor hm… or is it carburetor? 
But keep in mind that in the old days that was daily business. Mechanics were trained to do this and they knew how to because they did that several times a week. But if you do this (like most of us) once a year then no one can seriously claim to be able to set up the engine by ear only to run good. Most of us run their cars way too rich, a lot of meetings I go to I can hear engines sputter and bog because they run out of sync or are generally too rich. You can also smell the HC in the exhaust fumes. A good tuned engine also has exhaust fumes with a distinctive smell. 

The way I do it is: First I do the math, (Joke size x 4.1- 4.3) to get the mains and pop in 60 idle to get the thing running. I synchronise them with a sync tool and get the idle perfect (CO @ 3.5 4.5). It may be that one engine needs 60 idle jets amd another engine need 50's to get some progression on the idle mixture screw. Then I hook up my wideband O2 sensor and use a self made Air/Fuel ratio gauge. Then I go drive the car, feel it and monitor the A/F ratio. I can easily compare my feelings to the readings and see if I have to swap jets around to get the best transition of the different progression phases of the carburetor. For me this is the safest and most economic way to get a happy engine because I can not claim to have nor will I ever get the experience of an old Italian mechanic. Then to round it off I make a couple of runs with my G Tech RR Performance meter to see if the numbers improved. (for comparison you have to make the same runs before you change something on the engine)

My newest project has a Holley Performance Carburator and I have never dealt with such a thing.  But hey, the V8 guys tune them all the time so it can't be all that difficult 

By the way; what is the benefit of an expensive LM1 compared to a rather inexpensive Air/Fuel ratio gauge?

Cheers Dom 

[Bill Schwimmer]

Ear and intuition,  I can't even spell ML-1

[Cheesepanzer]

Good discussion.

It took me a year of trial and error to dial in my first IDA engine way back in 1982.  I say a year, but most people probably would say it was less than a half-hour.  However, I'm very picky.  I like my engines to run perfect.  I get frustrated very quickly if there's hesitation, rough transitions, poor idle, etc...  And as Shawn mentioned, weather affects the tune, sometimes dramatically.  So it can be aggrevating to know that one day its perfect and the next its "off".

There are two more things that are big factors to "open" (unfiltered) IDA engines.  It doesn't take very long for an IDA to get dirty inside the throats.  When I used to drive mine daily I would shoot some carb cleaner down the throats about once a week.  It was amazing and how much better and smoother the engine ran when the carbs were clean.  The second thing that I've noticed is the amount of fuel pressure being pushed to the carbs.  Too much and the only time it will run bitchin is under full throttle.   

[Zach Gomulka]

Imaging what the results would be if Roger had a LM-1. Probably better all over the rpm range.

For what its worth, I agree. 

Ear and intuition,  I can't even spell ML-1

Well, for starters its LM-1

[lawrence]

afr of 15-16 is way too lean. What size main is in it now? In fact, what is the entire venturi/jet stack setup?

New IDAs, third progression hole, 37mm venturies, 50 idle jet, 140 main, f 7 emulsion tube and 170 air corrector. Thanks for the reply syncro. I assume you have been to syncro de mayo  my high school shop teacher had a syncro they are cool.

[Bill Schwimmer]

Ear and intuition,  I can't even spell ML-1

Well, for starters its LM-1
[/quote]  See what I mean

[SlingShot]

Well very good debate we have here, I agree with both sides on this one. But I must say an LM-1, is still just an LM-1. It can't sense sound, smell, or feel, Which in my opinion are the basics in getting your motor to run well.
I.E.: When Zach and I were setting up my 1600 on the engine stand, the Kadrons were just not happy, popping, bad transition, you name it, the motor was running like crap. Had one of the old timers in town come over and check everything out. He noticed I had the linkage a little off (rookie mistake). We straightened that out, and it was a whole different motor.
I will eventually put a LM-1 on it just to try it out, I believe it has a finer sense of adjustment that "most" humans just don't have.  But it can't sence your linkage is a turn off

[n2o]

Is a carb syncro tool okay, but a/f meter is not okay???

Should be very easy to hear (even see) that the engine is out of sync.

I personally would not trust a dynoguy, or enginetuner that didn't have any experience with a/f-meter.

Would any of you?

thanks
Roar

[SOB/RFH]

Is a carb syncro tool okay, but a/f meter is not okay???

Should be very easy to hear (even see) that the engine is out of sync.

I personally would not trust a dynoguy, or enginetuner that didn't have any experience with a/f-meter.

Would any of you?

thanks
Roar

I don't think that the instruments or equipment being used is the only factor to recon when you choose a suplier. The best Swedish head porter that we have seen so far throw his flow bench out and went the route just pure intuition, I would have trusted him by the fact that he has allways delivered what was needed.

Remember, there is allways more then one way to skin a cat and the only thing that counts in the end is the result!!!

Happiness is a Hot VW!!

[BeetleBug]

Is a carb syncro tool okay, but a/f meter is not okay???

Should be very easy to hear (even see) that the engine is out of sync.

I personally would not trust a dynoguy, or enginetuner that didn't have any experience with a/f-meter.

Would any of you?

thanks
Roar

I don't think that the instruments or equipment being used is the only factor to recon when you choose a suplier. The best Swedish head porter that we have seen so far throw his flow bench out and went the route just pure intuition, I would have trusted him by the fact that he has allways delivered what was needed.

Remember, there is allways more then one way to skin a cat and the only thing that counts in the end is the result!!!

Happiness is a Hot VW!!

And who is he... and what made him the best head porter in Sweden?

[SOB/RFH]

Is a carb syncro tool okay, but a/f meter is not okay???

Should be very easy to hear (even see) that the engine is out of sync.

I personally would not trust a dynoguy, or enginetuner that didn't have any experience with a/f-meter.

Would any of you?

thanks
Roar

I don't think that the instruments or equipment being used is the only factor to recon when you choose a suplier. The best Swedish head porter that we have seen so far throw his flow bench out and went the route just pure intuition, I would have trusted him by the fact that he has allways delivered what was needed.

Remember, there is allways more then one way to skin a cat and the only thing that counts in the end is the result!!!

Happiness is a Hot VW!!

And who is he... and what made him the best head porter in Sweden?

'this topic is turning in to a "what is a streer car" topic. So I will give this answer and then I am out!!

The, to date best Swedish headporter was (Yeas he is dead now) Grottis. Grottis ported heads for fast street cars, drag cars and he was part of the development of Mopars Pro Stock motors back in the 90's. Avelan (can no more port heads due to severe case of white fingers) and Baker at Autoshop (Heis also dead since last summer) are the other two really big names when it comes to developing/porting heads for really high level racing here in Sweden. I have seen a few of there heads and they are all art when it comes to airflow but Grottis is still above the rest. One of the masterpieces done by Grottis was a set of Mopar Hemi heads that was totaly rebuilt from ground up, not billet but welded completele shut and then the new layout was done. Grottis did a lot of heads for the Pokemon crowd during his last years and they too proved winning combos. I do not know of any HiPo VW heads that Grottis did but he was consulted by one of my frieds in his development of  his VW type 1 Shaun Mcarthy 42*37 heads and some of the guidelines from that are benchmarks to me when it comes to the VW heads limitations and the 94 mm bore. Grottis did not use his flow bench while porting as he had a philosophy that it is not the flow number alone that makes it a winning combo, it is what the motor delivers that makes the numbers. His developing skills was first done while flowing heads, he then went to the dyno (and some flow bech use) and then eventially he was only in to real world (if dragracing = ET) numbers as they showd the result of the whole system. He ported heads for some 30 years as a living. This a Scandinavian perspective of things. As allways there will be "new guns" comming in to town and they will for sure prove to be better in the long run. But some names will stand above the rest, seen in a historic perspective.

So when it comes to carburators, to go back to the topic. I think drivabillity and performance can be achived if you know your carbs. If you adjust them by ear, analog instruments, digital instruments or even woodoo it is all ok to me.......as long as it is accepted that there are more  then one way to do things as long as you know how things cooperate togehter! Happiness is a Hot VW!!

[BeetleBug]

Is a carb syncro tool okay, but a/f meter is not okay???

Should be very easy to hear (even see) that the engine is out of sync.

I personally would not trust a dynoguy, or enginetuner that didn't have any experience with a/f-meter.

Would any of you?

thanks
Roar

I don't think that the instruments or equipment being used is the only factor to recon when you choose a suplier. The best Swedish head porter that we have seen so far throw his flow bench out and went the route just pure intuition, I would have trusted him by the fact that he has allways delivered what was needed.

Remember, there is allways more then one way to skin a cat and the only thing that counts in the end is the result!!!

Happiness is a Hot VW!!

And who is he... and what made him the best head porter in Sweden?

'this topic is turning in to a "what is a streer car" topic. So I will give this answer and then I am out!!

The, to date best Swedish headporter was (Yeas he is dead now) Grottis. Grottis ported heads for fast street cars, drag cars and he was part of the development of Mopars Pro Stock motors back in the 90's. Avelan (can no more port heads due to severe case of white fingers) and Baker at Autoshop (Heis also dead since last summer) are the other two really big names when it comes to developing/porting heads for really high level racing here in Sweden. I have seen a few of there heads and they are all art when it comes to airflow but Grottis is still above the rest. One of the masterpieces done by Grottis was a set of Mopar Hemi heads that was totaly rebuilt from ground up, not billet but welded completele shut and then the new layout was done. Grottis did a lot of heads for the Pokemon crowd during his last years and they too proved winning combos. I do not know of any HiPo VW heads that Grottis did but he was consulted by one of my frieds in his development of  his VW type 1 Shaun Mcarthy 42*37 heads and some of the guidelines from that are benchmarks to me when it comes to the VW heads limitations and the 94 mm bore. Grottis did not use his flow bench while porting as he had a philosophy that it is not the flow number alone that makes it a winning combo, it is what the motor delivers that makes the numbers. His developing skills was first done while flowing heads, he then went to the dyno (and some flow bech use) and then eventially he was only in to real world (if dragracing = ET) numbers as they showd the result of the whole system. He ported heads for some 30 years as a living. This a Scandinavian perspective of things. As allways there will be "new guns" comming in to town and they will for sure prove to be better in the long run. But some names will stand above the rest, seen in a historic perspective.

So when it comes to carburators, to go back to the topic. I think drivabillity and performance can be achived if you know your carbs. If you adjust them by ear, analog instruments, digital instruments or even woodoo it is all ok to me.......as long as it is accepted that there are more  then one way to do things as long as you know how things cooperate togehter! Happiness is a Hot VW!!

Takk SOB!

[ESH]

I'm lucky to have got to know a whole bunch of people that really know how to get things working properly and I'd say as an observer that it's a case of intuition and science. I have had people show me how to use various pieces of eqiupment but I don't have that second nature 'know how' so whilst certainly of use the tools only make up part of their potential in the hands of someone like myself but come into their own in the hands of those who really understand what they are doing. One thing I do know for sure is that the guys who know their shit have got to know it through a desire to learn more all the time and as such those guys will always make use of as much of the clever stuff that is available to them as they can. I guess one of the things intuition tells you is that there must always be a different and maybe better way of doing something and that's where science can come into play.

 

[Jon]

I don't think that the instruments or equipment being used is the only factor to recon when you choose a suplier.

Grottis did not use his flow bench while porting as he had a philosophy that it is not the flow number alone that makes it a winning combo, it is what the motor delivers that makes the numbers.

If you adjust them by ear, analog instruments, digital instruments or even woodoo it is all ok to me.......as long as it is accepted that there are more  than one way to do things as long as you know how things cooperate togehter! makes the numbers.

I agree fully...

[Cornpanzer]

IMO Experience and intuition will get you near right on for idle and full throttle, but it is tough to anylyze mid-ranges and transistions via "seat of the pants".   This is where your AF tools will help out the most.

[Harry/FDK]

Jim, PM send.

[Fastbrit]

IMO Experience and intuition will get you near right on for idle and full throttle

Ummm, is there any other throttle position?

[Jim Ratto]

IMO Experience and intuition will get you near right on for idle and full throttle

Ummm, is there any other throttle position?

 

[louisb]

Just a note. I was on eBay and noticed several LM-1s for a little over $200 and one with the rpm chip for just under $300. That is a pretty good price and makes it within reach of most people.

--louis

[lawrence]

Side note update I replaced the 135 main jets in my carbs for 140 and the motor is happier than before. Very little stumble between idle and main transition now. I will probably just leave it and DRIVE!! Will have to wait for the rain to clear a little