The Cal-look Lounge

Sometimes all the bar graphs, pie charts, calculations and slide rulers mean less than "just knowing when things are right".

It's funny, guys can read volumes of info about Weber carbs, follow all the charts and diagrams and math and in the end, the motor runs like a pile of junk. These guys insist that they've "gone by the book" and squeezed all they can from the motor. A friend of mine up north was trying to get a motor tuned in for a customer, but the customer insisted "the Weber chart says this size motor needs this jet, no bigger!" and the result was a popping, leaned out wimp.

Mark Herbert used to post on the old CLF one of my favorite quotes of his: "Let's go race calculators"

I remember a post on CLF about jetting and some guys insisting "you need an LM1" and Clyde Berg came in and said something about "if a car runs right, then you've got it, without the sensor"

Is it science or good old intuition?

To me I think it is "knowing" when a car is "right" and knowing a baseline. Then getting to the baseline and knowing how to improve on it, no matter what the books say. The charts and all are great for getting a starting point, but sometimes the suggestions published are so far off for a particular application, it's a wonder they'll even run at all.

Anyway, thought I'd start a discussion about going beyond the math, and using your "gut feeling" to make the car go faster.
Any thoughts?

About the LM-1.... if you have ever used one, you'd know. My buddies IDA'd 2276 ran like a champ, tuned by traditional methods made 198hp with pump gas on the dyno, and ran 12.6's @ 105- in a true 100% daily driven street car. Got the LM-1 on there and it showed that the AF ratio was waaayy of in some spots. So we tinkered with the jets until the LM-1 was happy. The result was an engine that transitioned from idle circuts to mains much more smoothly, and got 25mpg if you could keep your foot out of it. And it was just as fast at the track. My .02 ;)

what was changed after LM-1 was installed?

I forgot to mention.... in a word, everything. Different emulsions, idle airs, idle fuels, mains and airs. You would have never thought that it was that far "off". Im sold on the LM-1, Ill be hooking one up to the GTV soon with hopes of improved mileage and performance. Ill let ya'll know how it goes.

It is also the tool my friend used to get his 1915 powered '67 in to the 13's, on pump gas, with radials, through 3 stock gears ;)

hmm. When running a 2276 on Heads Up's dyno, we pulled a 202 @ 7000 and 161 ft lb @ 5500. Roger said "try F11 tubes instead of your F7's and watch what happens", we left jets and timing alone. No air/fuel sensor. Pulled 213 @ 7100 and 175 ft lb @ 5500. That's the kind of "knowing" and "experience" that impresses me.
My old boss Jerry, he was much of the same way. He could listen to my car leave the parking lot at work and next day, he'd say "needs more main". So I'd swap up and bingo.

I had an uncle that was like that. Could tune an engine by sound and the feel of its vibration. He had also been doing it for fifty years. Me, I am not that good and will be getting an LM1 as soon as I can afford one. I think one of the problems with "By the Book" people is that their information doesn't take into account that each engine is different. I have seen two identically built engines need different jets and timing. (Not a huge difference but still not the same.) I think that is why you have to pay attention to that specific engine on that day.

--louis

You forget to mention that Travis is an engineer, and will endlessly tinker.  He digs toys.  A LM-1 is a pretty cool tool.

When I first put two dual barrel carbs on my car when I was 17 I was scared to death to get them set. I could get them to pull same amount of air, but jetting and getting mixture set was a Black Art. I got them in as close as possible and took it to Jerry so he could give them a once over. Amazingly, he said I got them really close and just adjusted the air bleed circuits. When I graduated up to 44IDFs in a few years, again I was a little intimidated. But from getting the previous Dellortos set, I knew what was "right" in my book. And again Jerry helped out. I could get the carbs to idle and run steady state, but would hesitate in transition. Jerry heard it run one day and when I got back to shop, in his most typical "Jerry" tone of voice said "I KNOW you didn't leave those goddamn size 50 idle jets in that motherf**ker." With that said, he knew I had. Tried 55's and the difference was night and day. Dicked around more with it, went to 57 idle, opened air bleeds a bit, and it was perfect.
By the time I had a set of 48IDAs in 1991 I was pretty confident in making them run decently. Setting the floats and so on was easy (even with carbs on the car, thanks to help from friend Steve Fuss) and getting them to do what they should was pretty easy. By now it wasn't so much "book says turn the screw 1-1/4 turns with X-size jet..." it was more knowing how the exhaust should sound, smell, the amount of heat coming off the header and what to do to get it all right, and it took a long time and the inhalation of a lot of fumes, but eventually I got it. That was part of the fun of always trying something new (cam/heads/etc) in my car....setting carbs up to make whatever combo happy. After a few years @ Buggy House it was like I had gained respect from Jerry too, he'd get a Weber car in there with a soft idle or a dead spot somewhere, and ask me what I thought.

I guess my point to this post is that while, yes, the sensor and the equations are fantastic tools for a guy to dial his combination in with, there is still something cool about guys like Jerry, and your uncle Louis. These guys cut their teeth on setting stuff up when the only TV's you could buy was black and white. And not only carbs. How a set of heads won't "work" on some motor, or how "no matter which damn motor you drop that cam in, it's gonna rip your head off"....these kind of guys are invaluable and a bit of a rare breed.  I don't know if any of you know Tony Wilkie, but he's around my age, and he definitely belongs to this group. He could quietly stand by, listen to a car and pinpoint what it needed. Amazing guy.

I think that making a vw to go like hell is a bit of science and intuition,i rely mostly on intuition as i'm more old skool like ;D

But i think the Lm can be usefull although i never used it.
Dave Kawell that builds my drag engines relies on intuition too,up till now never seen him use the LM 8)

I am sorta at the start of that with these Kads I have been trying to set up on the 1500. Reading spark plugs is one of those black arts I am just really getting the hang of, sorta. Never tuned an engine with a split, or semi-split manifold like these kads have. I keep going around in circles with the damn things.  :D And this is only with two one barrels, can't wait to try it with the IDAs. My biggest problem is making too many changes at once or too quickly. I have to remind myself to sit and listen to the engine, the rhythm of the exhaust, the air flow into the carbs, feel the engine vibrate as it turns over, etc.

Here is one for you though not motor related. My dad was in charge of the printing shop for a two year college here in town. One of the guys who worked there was deaf. He could tell if the printing presses were running right by the way they vibrated as they ran. He usually would know if something was wrong before the other operators who could hear.

--louis

somewhere I read that the infamous Cosworth DFV Formula 1 heads was designed more from "gut feeling" than science by Costin and Duckworth. Look how that turned out.

I think more and more people use the LM1 and other tools because there arn't that many people who really know their way with carburators.Most mechanics who learned it during their years of working with carbs are getting older now .The young guys coming out of school as a mechanic nowadays know where to plug in the computer in the car and it will tell them which item should be replaced.

I'm playing with volkswagens for over 12 years now and during the last 3 years it is that I really started to understand what every part of a carb does.

michael

louis, that's cool you brought this up. When I mess with carbs, setting mixtures, I probably use 60% sound, 40% vibration to get them set. I leave screwdriver on mixture screw and use it to feel what the motor is doing. Like feeling its pulse.

very good point Michael!

I can agree with that. Finding a "professional" who knows anything about VWs in my town is a pita. If it is not in their computer they don't know what to do. Found this out the hard way a couple of weeks ago when I went to have the alignment done on my '67. Only person in town who could do it was some ancient little hole in the wall place that still set the suspension manually. And even then they couldn't do the rear. For the life of me I couldn't convince the guy that the rear wheels shold have that much camber when you jack the back end off the ground. He wanted me to take it home and lower the back end a couple of inches so the tires would not have so much camber.  ::)

That also comes into the reason I want an LM1. There is not anyone else around here to ask if it is right or wrong. Until I am more confident I want a second opinion even if it is a little black box. I think I own the only set of IDAs in town and I know I am the only VW in our club with dual carbs.

--louis

[/quote] I think I own the only set of IDAs in town and I know I am the only VW in our club with dual carbs.

--louis
[/quote]

well louis it's lonely at the top but never crowdy ;D

i think the LM-1 and other tools are great and of great benefit to all builders. that is because the persons who actually can hear and feel an engine that good are as rare now as they where then. besides, people have opinions and ideas and blackboxes have one too, but it is all the same opinion. so what works for one engine or person doesn't work for another. if i look at the charts of jets in my 40IDFs it would say a mainjet between 117 and 128 or something along those lines. and if i asked around people told me to put in a 125, that worked OK, but the guy i went to who build the engine said that a 115 would work best. i have switched jets a lot and found that sometimes the smaller worked better and other times the bigger ones. all this to say that indeed there are a lot of things that have to be taken into account. and that is only achieved by knowledge and experience.

I think this is also the reason engines get bigger and bigger.How will it be in say 10 or 15 years.How much of the know how will be there for whoever wishes to build or tune an engine?

The computer makes everything easier but in my opinion makes knowhow get lost.

michael

we use one with our race engine at the track - we know it's close when we leave home - but it sure does work to get the most out of your engine - there is a big gap in the vw game - we have us old schoolers - and then you have the new kids - how grew up with using computers - for them its a no brainer - use to using this stuff - so its both - science and gut feeling

People can learn the mechanics or "theory" of just about anything.  Not everybody can put it to use and get results.  You just can't replace talent.

I cant believe how stubborn a lot of you guys are when it comes to new technology. And I thought I was bad!  ::)

The 2276 I mentioned before was tuned very well prior to the LM-1, using the dyno and monitoring the BSFC (brake specific fuel consumption), by my friend Travis Alward and Steve Hollingsworth (knows his way around a VW motor, to say the least). I think Howard Washington was there to give his .02 as well. It was further dialed in after installation into the car. My point is that these were not some ham fisted idiots making guesses as to what the engine wanted, and the LM-1 still made it that much better.

There is no substitute for knowing the exact AF ratio at any given moment, I dont care how long you have been doing this, or how good your ear is.

Hey now, I resemble that remark.   :D

I am not so sure it is resistance to new tech, but nostalgia for the way things have been done in the past. We drive old cars that run off of antiquated carburetors. We like the sensation of being intimate with the car. (Not intimate that way.  ::) ) I work in the world of bits and bytes every day. One of the things I love about my VW is that most advanced electrical component on the car is the AM radio. (Well, until I stuck that Pertronix kit in the 010 last weekend.) There is what, seven wires in the whole damn car. It speaks of old world craftsmanship and simpler times. Plus it scores major manly points if you can do it without some magic black box. Having said that, I still plan to save up for one.   ;)

--louis

The LM-1 is a good tool to utilize, but I would not rely on it soley. Tinkering and tuning ability used in conjuction with the LM-1 is a good combination. I have used an LM-1 on a few occations to tune my 1914 with IDAs.

The sizing of my idle jets is a perfect example of using the traditional and technolgical methods of tuning. I previously had 55 idle jets and I knew the car was running rich because the exhaust smell was very strong and the car idled like crap at operating temp. I could also turn the mixture screws on the passenger side carb all the way in and it would still run. So, I hooked up a borrowed LM-1 and bingo the car was running too rich at idle. I put 50 idle jets in, although many people told me they were too small, and the car idles great now.

My next issue relates back to Jims original point. The car stumbles and goes lean in the transition from idles to mains, but runs good while cruising. I dont really want to fool with it because the a/f ratio is between 15-16, which the dellorto manual says is most fuel efficient. So should I bump the main up one size? Help me out tuners  ;D

I think ALL of you are right! But you are talking about differnt things I think.
Making the IDA run sweet takes time experience and good ears...
Making it run "on the line" of performance rich/lean takes a lot of reading plugs or one hell of a set of ears.
...or a LM1

But remember the LM1 doesn't tune your IDAs... you do.... and it's you that need the skills.

I agree with what Michael posted ;D

Tuning is science and intuition and it takes a lot of time to do properly. You need to know what works and you need to get the ear/skill to pull the last bits of power out of it. So just looking at flow numbers and calculus results is not the way to go. I think competence is the right word as it is defined as the knowledge and experience. It also takes some guts to really use what you have put together!! A very good topic this!!

Your engine tells you what it needs, not the other way around.  It is a skill which is learned, just some learn quicker ;)   I have a LM-1 and I would not
want to give it up.  It amazes me how much the a/f varies with the weather.
Don't be afraid of making changes, just make one at a time and drive it.
Good thread  8)

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?

Brilliant answer!

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

Personally I like the "seat of the pants" tunning!  And when I need to finetune my engine, I pull my pants down to get "just the right" feeling. LOL

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. :o 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.  ;D

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.  :o But hey, the V8 guys tune them all the time so it can't be all that difficult  ;D

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

Cheers Dom  8)

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

Good discussion. 8)

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.   ;)

For what its worth, I agree.  ::)


Well, for starters its LM-1 ;) ;D

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.

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

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 ;D

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!

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.

 :)

I agree fully...

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.

Jim, PM send.

Ummm, is there any other throttle position? ??? :-*

 ;D

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

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 :(