SU's or Weber/mikuni

[madkaw]

Steve,

you haven't tried the shut-off switch yet for the fuel smell?

I think just breaking in a motor and and getting bugs worked out in your new engine is a great place for SUs. Though the Mikuni's and or Webers can be made to run better than the SU's, the SU's being more simplistic are a better way to get started. It's important to break in a motor properly and I wouldn't want to be dialing in triples on the fly with a new motor.

Now Todd at Wolfcreek could get you close with a rebuilt set and you might get lucky to dial it in fast, but the SU's are almost full proof and cheaper to rebuild and maintain. Oncce you get the motor where you want, someone will gladly buy your SU's so you can upgrade.

[cbuczesk]

Steve,

you haven't tried the shut-off switch yet for the fuel smell?

I think just breaking in a motor and and getting bugs worked out in your new engine is a great place for SUs. Though the Mikuni's and or Webers can be made to run better than the SU's, the SU's being more simplistic are a better way to get started. It's important to break in a motor properly and I wouldn't want to be dialing in triples on the fly with a new motor.

Now Todd at Wolfcreek could get you close with a rebuilt set and you might get lucky to dial it in fast, but the SU's are almost full proof and cheaper to rebuild and maintain. Oncce you get the motor where you want, someone will gladly buy your SU's so you can upgrade.

I agree. I rebuilt the 440 6bbl for my Road Runner but used a working Holley 4bbl to break in the engine.

Chuck

[MotoManMike]

I've been running 15% here for about 2 years in SU round tops with no issues. Be weary if any of your carbs you want to run have rubber parts with ethanol, it will shrink the rubber up and cause problems tuning. I've rebuilt more ATV carburetors than I ever have since they introduced this ethanol mess. they use a rubber tipped float valve and the rubber shrinks up and cracks due to the ethanol. SU carbs are old school so they have been unaffected as none of the rubber parts are exposed to fuel. Cork and brass, they did it right .

[Lazeum]

I haven't run SU's so I can really compare them.

Fact is I love my DCOE, I barely have to touch them, they stay tuned and the sound!!!! You need however to understand how they work & find a way to tune them: Jets library ($$$) + wideband were my tools.

Driveability with DCOE could be great, MPG could also be reasonable but you need to have carbs AND timing setup correctly. I made a 200mi trip at 21 mpg average.

Don't forget you can set your side draft with bigger or smaller chokes, you don't have to get super large carbs & chokes to enjoy your engine (it's actually quite the opposite). Smaller carbs would provide a good torque at low rpm. This choice will also depend on our head setup (comp ratio, cam profile, etc.)

So think also about what would have to go around with side-drafts: recurved dizzy or fully adjustable, timing light, jets library, wideband, books, etc. That would add up some hundreds of $$$ more.

Edited July 23, 2012 by Lazeum

[Bruce Palmer]

You know, this thread is an exact reason I have no problem sending guys with questions here to find some real information rather than some of the nonesense I see elsewhere. Whatever side of an issue you think you are on, you can generally find intelligent discussion here.

[5thhorsemann]

You know, this thread is an exact reason I have no problem sending guys with questions here to find some real information rather than some of the nonesense I see elsewhere. Whatever side of an issue you think you are on, you can generally find intelligent discussion here.

Agreed, but grannyknot hasn't come back, I think we may have added to his dilemma. Unfortunately there is no hard and fast answer to his question, these are all good intakes, and all will perform well on his new motor. I guess the summary reply is, it all depends on his expertise, his willingness to study the chosen design and his ability to shell out the bucks necessary to make it happen.

[grannyknot]

Agreed, but grannyknot hasn't come back, I think we may have added to his dilemma. Unfortunately there is no hard and fast answer to his question, these are all good intakes, and all will perform well on his new motor. I guess the summary reply is, it all depends on his expertise, his willingness to study the chosen design and his ability to shell out the bucks necessary to make it happen.

5thhorsemann hits the nail on the head twice in a row!

Dilemma is the word, I thank everyone for their advice but it's all like the archives. I was hoping someone had done a back to back dyno with SU's and tripples that could end the debate but I guess not, maybe I'll do it!

I will start with the SU's and go from there,

Chris

[LeonV]

5thhorsemann hits the nail on the head twice in a row!

Dilemma is the word, I thank everyone for their advice but it's all like the archives. I was hoping someone had done a back to back dyno with SU's and tripples that could end the debate but I guess not, maybe I'll do it!

I will start with the SU's and go from there,

Chris

Properly tuned, triples will always make more power than SUs. It has been done, thousands of times. If you're looking for dyno results, search hybridz.org.

[hls30.com]

In the not to distant past one of the Magazines(I believe it was either ClassicMotorsports or GrassRoots Motorsports) did a head to head contest between Webbers and Sus on a given engine, I have it somewhere, and I believe the result was six of one half a dozen of the other-meaning only marginal differences when both are tuned properly. If my memory serves that article correctly, that means there are more effective ways to spend that money. I'll hunt the article and post it when I find it. On the other side of the coin, Nissan did choose Mikunis for the performace sports versions for a reason.

Will

[madkaw]

5thhorsemann hits the nail on the head twice in a row!

Dilemma is the word, I thank everyone for their advice but it's all like the archives. I was hoping someone had done a back to back dyno with SU's and tripples that could end the debate but I guess not, maybe I'll do it!

I will start with the SU's and go from there,

Chris

Well hopefully I will have your back to back results soon. I ran 155 RWHP with my SU's and now have installed the triples with no changes to the engine. My goal has been to be systematic about upgrades because I want to be sure I am moving foward and not being decieved by the butt dyno. It will atleast a month, but I will be back at the dyno when I think I have my jetting really close.

[Stanley]

No experience with the trips but just looking at it the triples manifold has 6 short, equal runners. Could that have as much to do with performance as the carbs? BTW since I'm not much of a mechanic I love it that I've got SU's - really simple for a performance carb. And all the help: yesterday found a sticking nozzle and wondered if I should grease it or not - found 5 threads here about exactly that.

[hls30.com]

The article is in issue 146 (September 2010) of Classic MotorSports Magazine

Nothing to scan it with at the moment.

Edited July 29, 2012 by hls30.com