ITC Carb choice's

I

iambhooper

New member
Just wondering what everyone is running for a carb? I'm using a stock carb, with Holley jets. I've seen some of the Weber carbed caes perform well, and some bad. Is the webber an upgrade on a jetted stock unit?

Thanks !
 
My personal experiences:
DGV Weber - makes the most power, highly adjustable, but absolutely the worst "driveability". Throttle response isn't great and it can/will stumble in most left hand corners. Yet despite that, I'm usually fastest with this carb, unless on a tighter and twistier track.

DMTR Weber - doesn't make quite the power of the DGV, but highly adjustable and has pretty darn good driveability. Utilizes a split float design versus the DGV's single float design, resulting in better and more predictable response in corners and no stumbling.

Modified Honda carb - if set up correctly, see's similar power to the DMTR and is very driveable, but they're hardly adjustable at all and are very difficult to work on yourself. I know there are several very quick ITC Honda's out there running modifies stock carbs, but I always had a hard time getting them to work well for me. Plus I could never fiddle with these myself like I could with a Weber. If I didn't like the way it ran, I had to send it out again to someone who claimed they knew what they were doing.
 
The starvation of the DGV, does that occur in hard left hander's, or all left handers? I aim to race 3-5 weekends a year, with most of those at VIR. I don't know if you are familiar with the track configuration, but it has 1 hard lefty, and 3 "soft" lefty's.

If I went this route, and ran at a track such as Kershaw, I could always run my stock carb.

My car had always been reasonably fast, considering it had a stock motor, massaged carb, and the 4.4 final drive. However, I spun a bearing in May and put a rod through the block. I'm in the process of building a new engine, and have some decisions to make. I am going to do a .040 over block, but hadn't put much thought into the carb... until now.

Thanks!
hoop
 
It doesn't cough in every, single left hander. At Mid Ohio it'll cough a little bit in turns 1 & 7 and then worse in turn 13. The rest of the left handers (3, 9, & 16), it doesn't cough at all. The DGV is still the fastest there though due to the increased power. The difference is the more violent you have to turn the car in and the longer the corner is, the worse it'll cough.

At Road Atlanta, it coughed some in turn 5 and then worse in turn 10a. With the long straights and few left handers at that track, the DGV was easily fastest.

Again, this is all "In my experience!". Others may have different results.

There are people out there who claim that they can eliminate the coughing problem with the DGV but I've never tried one out. However, I plan to send out a DGV to one of them probably this week and then trying it out in about a month at Mid Ohio. It's ~$150 and includes a full rebuild of the carb (which it needs anyway), complete jetting to your car, build, and use, and then whatever mods they do to solve the coughing. It sounded resonable enough to try it out once, even if they do end up to be full of shit.
 
just as a note . All three Marrs cars you saw in May are running modified stock carbs
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Is this Martin? So you guys are running the modified stock carb? We were all pretty close... except you seemed to have a little leg on the straights. So what was the difference there? 40 over or final drive?

Don't take this wrong, cause it's not meant as a slam at all, but I know it wasn't exit speed onto the straights. I was all over most of the Marrs crowd (John, Beth and I never really got a chance to run together) in the corners, only to be out pulled down the straight a bit. Granted, I was stuck in a fight with mostly 90/91 civics... but they shouldn't be any different.

hoop
 
What Kevin said about the various carbs is right, but let me modify that. I've just spent several years trying to perfect a Weber 34/34 DMTR. It makes an interesting paper weight. There are those out there that know how to make them run, but they aren't telling how. I've heard exact opposite settings from two different drivers who have won the ARRC using it. I could never get it to stop stumbling...exactly opposite of what I was told it would do. The Honda carb is excellent in drivability, but limited on horsepower. Only one person I'm aware of has made it really strong, but he's at his limit. Plus, you are really limited on timing changes as you will burn a piston if you run it too high with the stock carb. The Weber DGV 32/36 is the best carb for horsepower, but it is EXTREMELY difficult to make not stumble in almost every turn. The secret of making it not stumble is to stay above the cut off of the high speed siphoning jet. That means you never slow down! Don't worry, and Honda handles better than you think...I think...I'm just learning that.
 
So, what's the cut off limit of the DGV? 3500, 4000, 5000 RPM's? Will it stumble in the right hand corners, as well as the lefty's? Chris, what your saying is the exact opposite of what Kevin said?... kinda goes along with your theory anyway, doesn't it?

Several of the C cars out there are using a Weber... I know John Fine is (although I understand he had some problems at Kershaw recently, possibly fuel related), and Mark Senior was using one. Mark was really fast around VIR (usually top 2 of the class on the fast days).

Any other opinions, votes? What exactly is the DGEV, DGAV, DFV, DATRA stuff? Is there a good resource to read that explains all this stuff?

I did notice that Rivergate race preps the stock carb's, if that means anything.

hoop
 
As a DMTR user (non-Honda), you have to be aware that in Weber"s infinite wisdom, they made a whole bunch of different DMTR(s). There is a model designation stamped in the base of the carb. The numbers are significant.

If you find someone with a Honda that likes their DMTR, find out the precise model, then inquire about jetting, air filters and float level settings.

Cheers.
 
Yes, there are several models of DMTR's...I only tried two of them with the same results in both cases. The only time I could elimate the stumble was to plug the high speed siphoning jet. It was amazingly smooth and easy to drive, but a slug in the straights without it. If I let the revs get below 4500 in the turns, it would stumble at 45, 48, 5, and 5300. Holding the throttle down was fruitless, the only way to clear it was to lift or go with a half throttle position to get it running past the stumble points.

I've never run the stock carb, so I only have reports of others opinions and problems. OPM sells and preps them as does Rivergate. The only really fast car (I'm aware of) that runs one comes from the Rivergate shop. I'm certain that others will take umbrage on that, but I'm not trying to be critical. I use the performance of the different carb on cars I've seen run at the ARRC and other tracks as my sampling. Vesa Siligren ran a 34/34 DMTR on his Civic and did well, but he changed to a 32/36 DGV last year and is really fast. He was the only person that gave me reliable advice on my DMTR, but even he gave it up. I don't know what kind of carb Mark Senior was running. I've only raced him once at Daytona. My car was running bad on my carb, and his was running good. I had the handling and he had the horsepower. He could just drive away, and I couldn't maintain a draft. I beat him, but I had help in the form of a SM with an idiot behind the wheel (where have I heard that before).

My 32/36 is new and is in the process of development. I've got arguably the best guy in the country racing a Honda with this carb on it doing the development. It's not perfect, it does stumble on hard left turns and some slow right turns due to the float configuration. It is amazing the difference in power and top end! The stumbling is so brief, as opposed to the old carb, that it really doesn't bother me that much. As a point of reference (again), I recently ran at the same Memphis Motorsports Park course I've run for several years in my ITC Civic and in my ITA Civic (1st gen). I ran 2 seconds faster this May than I've ever ran in the C car and a 1/2 second faster than the A. That's horsepower!

Drivabilty is critical, but remember, the finish line is always on the straight.

If you've got any questions, feel free to ask. But I can't tell you who's working on my car or too much of what he's doing. I will say it's all totally legal.
 
So that's another vote for the DGV? Is there a model number on the one you are using?

Chris, I would have to say the chances of us racing against each other a slim. Of course if RA is on the way out, I'm sure that leaves an opportunity for us to meet.

How does your car pull against Fine's?

hoop
 
So that's another vote for the DGV? Is there a model number on the one you are using?

Chris, I would have to say the chances of us racing against each other a slim. Of course if RA is on the way out, I'm sure that leaves an opportunity for us to meet.

How does your car pull against Fine's?

hoop
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If I can drive from Baton Rouge to Atlanta or Daytona to race, you can make it this summer to Atlanta from Northern Carolina. lol I'll have to look to find the model number, as I don't remember it off hand. It was a DGEV rather than a DGAV that you hear more about. The difference between the E and the A is the Italian for the type choke activation...electric or water(aqua).

I'm not going to say how I pulled against Fine as I've only ran against him twice...once last year at Atlanta with the old carb and a broken exhaust header (found after the weekend was done)...he had me by a couple of seconds at least. The second time was this May at Daytona. He out qualified me by a little...again, I had trouble that I didn't find until later (note to self, don't go this far without a crew). I ran 3 seconds slower than last summer, but I found two weak valve springs, with two screwed valve stems, and the accelerator pump linkage came loose during the race. I was killed by a wasted CV joint. One of the his drivers turned the fastest lap in ITC, but it was slower by a second of what I've turned before.

All excuses aside, on the start, I smoked him, and within ten laps of a 1.5 hr enduro, I'd moved into second from fourth and had 1/2 a lap on Fine. But in order to be declared a finisher, you must first finish. I did get to watch the race from a cool spot! :birra:
 
those oval "road" courses can be rough, eh? that's a lot of trauma to suffer in two weekends.

alas... i will not be making it any where this summer. if i'm lucky, maybe late fall. the block's at the machine shop now, it probably won't be back for several weeks. nontheless, i wan't to do it the right way, and put a better product back on the track... which means i may need to replace a few bushings, and who knows. october... more likely march.

so, dgev, or dgav, then? i guess i need to know which one to look for. is best to start with a brand new one, or is it ok to start with a good used one and a rebuild kit?

hoop
 
New...never buy a used one unless it comes from your father. If you don't know exactly whats been done to the carb, you can end up with something that's been drilled and screwed to death. Consider this, if someone's selling a carb, it either came from a wreck and might be damaged, or the guy could never get it to work and is selling it to get the money to start all over again. Ex. I'd sell my old DMTR's for 5 Pesos, but they no longer exist in my used car parts inventory.
 
Chris, I think I tried to pull some of those DGV secrets out of the guy I'd guess is setting up yours right now at the Saturday night OPM party at last years ARRC. He didn't budge! :P
 
That's the one, Kevin. He's the only guy that I know that's been able to make one run flawlessly, but it's taken a long time to get there. He tells me what he's doing when he adjusts it, but my comprehension level is way behind the curve. I understood the DMTR, but could never make it right. Don't worry, you aren't the only one he's tight lipped to. Even though he works on my car all the time, he's stated that there are some things he's learned from trial and error that he just won't share. I hope he sells his car so he'll free up the advice.
By the way, he's on a long term development of a CRX for ITA. It took him three years to get his C car ready to race, and we know the results of that effort, so watch your mirrors in the not to distant future. :D
 
ok ya'll are a bit more in the "in" group among the lower SE crowd than i am, so your talking amongst yourselves there.

so, if i get a DGAV, any tips? in all honesty, with this engine build i probably won't be back on the track until march, so i need to do it right.
 
Chris, I tried to get him to pull his DGV on Saturday night and let me run it on my car during Sunday's enduro. He didn't go for that. :P For some reason I thought he had sold his car already, but I guess I was mistaken. It'll be fun to see him in an ITA car though!

hoop, my suggestion would be to get a DGV. I really can't comment on which "model" (DGAV, DGEV, etc.)or whatever to get because I really don't know the differences between them.
 
Kevin, the only time I've known him to take his carb off his car and put it on another one was at an enduro we ran several years ago. It was an attempt to figure if the DGAV was better than the DMTR. For various reasons, it failed miserably and was impossible to drive. Since then, the only time it's left his intake is for maintenance or in impound at Atlanta after a win.

Hoop, contact a business like Redline or another reputable carb dealer. Tell them what you have, and what you want to do with it. Businesses like these deal on a tight margine of customer satisfaction. If they can help you, they will. Don't worry about being blown off or screwed around. If you now what you want or need, you can get it from serveral of the many race car parts distributors. I was fortunate in that Evan had connections in Florida that got me what I needed. It came complete and intacted on a blister pack with all the parts from the air cleaner to the adapter plate. Price was spot on. It was a DGEV, which mean "electric" choke. You take that off immediately. It's useless and legal to remove. Same for the "agua" in the DGAV. Then you take it apart, clean it up with solvent, and put it back on. As they say...let the tuning begin! Make small adjustments in jetting and careful adjustments in the float level. For obvious reasons, the float level is critical.

Remember, there are a bunch of designs of DGAV's. The one for a formula ford will not be legal for a Honda. That's why I said to tell a reputable dealer what you have and what you want to do with it. I have a good friend that bought a DGAV for his Honda from a very good friend who built FF motors. It was a good price, but completely useless for his application. If he ever goes to FF racing, he already has a spare carb. :D
 
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