Jump to content
HybridZ

To use triple carbs or not..that is the question!!


Guest Stoker3.0Z

Recommended Posts

  • Replies 87
  • Created
  • Last Reply

Top Posters In This Topic

By the way , the producer of "FULL THROTTLE" ordered 2 of my intakes, never asked my advice or opinion as to what carb, linkage, ignition, timing, exhaust etc.

They were installed by "mechanics" with obviously no experience on engines of unknown condition. Results were as dismall as I would expect.

Glad I got paid for the intakes.

Dave

 

http://www.arizonazcar.com

ARIZONA Z CAR

2043 E. QUARTZ ST.

MESA AZ 85213

Phone 480-844-9677

E-mail dave@arizonazcar.com

Link to comment
Share on other sites

Id probably do the 4bbl over triple webbers on a highly modified motor due to my past v8 experience. I dont know if they made a quadrajet small enough to run on an L6 NA but I would probably use one of those if they since I love how they can make a car run when tuned right. Other than that it would be the good old 4bbl holley, easy enough to tune and rebuild. My efi is running well and I got lucky enough to pick up spares of every known wear part in the system, doubles of some. Other than the 4bbl, the SU's are a very good setup when they run right.

Link to comment
Share on other sites

I dont' want to offend anybody here.. but I would never run a 4bl setup on a Z motor.

 

It's just the ethics of it to me... I'd also never put a v8 in my Z...

I like to keep an import.. imported.

just my theory anyway.

-Ed

 

Heh.. Methinks you are on the wrong web site then.. :twak::lol:

Link to comment
Share on other sites

  • Administrators

Well, as I said above, I think EGT it is not a very good tool to measure the A/F ratio of individual cylinders.

 

Way too many variables could affect the EGT of each cylinder with A/F ratio only being one of them. Things that could vary from cylinder to cylinder like ignition timing, true cylinder volume, hot spots in the head/block, radiated heat from the exhaust manifold etc. etc. etc.

 

I agree that EGT is a great tuning tool and helps you look into what is going on inside the engine and allows you to find problems and correct them, I was not saying it was not.

 

But, here is my problem. One of the great advantages that the triples (since we seem to be talking about them and not SU’s anymore) have over the 4bbl and even the SU’s is the ability to adjust the A/F ratio etc for each cylinder, and along the same train of thought the ability to mask or cover up other problems / deficiencies on a per-cylinder basis.

 

 

As mentioned on other threads I too feel that the over enthusiastic converts that feel that the 4BBL conversion is the end all solution to poor carburetion… I myself do not believe this either. You have a multitude of scenarios that can be pro or con. A few examples that come to mind are.

 

 

  • Dude has a car with a healthy L6 in it. Good compression and mechanically in great shape but the old SU’s are shot. He buys a 4bbl intake, slaps his favorite type of carb on it and bam! It’s running bitchen. Of course it will compared to a worn out set of SU’s but the advantage goes to the 4bbl in this case.
  • Same scenario as above except that he gets himself a nice set of Z-Therapy rebuilt SU’s, slaps them on. Advantage SU’s.
  • Another scenario and one that has been brought up before and I think really is what gives the 4bbl a bad rap. Dude has car that runs like crap, engine is just worn out and compression is all over the map, lot’s of factors here that could be causing this but I will just make up one for the sake of argument. He makes adjustments to the stock SU’s to get it to run for the most part. The ability to tune 2 separate banks with the SU’s my even play into this, if let’s say for example 1 or 2 cylinders are way down on compression and they are the 2 near the fire wall then by adjusting that carb he could in theory get the car to run ok… kinda. He gets feed up and convinces himself that the carbs are the problem and goes out and buys a 4bbl setup, slaps it on. I don’t think it will take a PhD to figure out what is going to happen next. Now, he is really PO’ed throws the 4bbl in the trash can and buys some nice rebuilt SU’s, tunes it, car runs better, well of course it does, getting rid of the worn out SU’s should help the situation (but could even make worse in some cases) but having the ability to mask an underlying problem by tweaking the individual carbs is just a cover up, the problem is still there and will need to be addressed.

 

One of my favorite phrases that I hear a lot about SU’s just crack me up “… they are such a simple design and so easy to tune” You have got to be kidding me?

 

What the hell have I been thinking all this time? You are so right, a very old simple designed carb must be far superior to a new modern day type of carburetion. Hell, EFI is so complicated it must be a complete P.O.S. also…. I really wish I could find a carb large enough for my car that uses the same simple design that my lawnmower engine has.

 

All right, enough of the sarcasm. At this point I feel like I need to bow out of this thread because I hijacked it from Mike (Stroker 3.0Z) and would like to apologize to him because his original question was regarding triple carbs and not 4bbl carbs and I took this in another direction.

The reason jumped on this is because I am getting sick of hearing claims from people about problems with 4bbl applications that have no technical merit behind it.

 

TonyD, thanks for the info you have provided as it has given me a lot to consider and the fact that you have done testing that compares different setups is a breath of fresh air and I would to hear more about what you had found with regards to above 6500 rpm performance… very good info so far.

 

BTW, yes I do have an ArizonaZ 4bbl intake, but that only has a little to do with my opinion on the subject. So far the car runs fantastic but… I have not done enough testing and tuning as I have all the suspension out right now for a full rebuild. As soon as I get it back together I plan on working with my intake setup and will share my finding for those who are interested.

 

 

Thanks,

 

Dan

Link to comment
Share on other sites

  • Administrators

 

Originally Posted by Nismo280zEd

I dont' want to offend anybody here.. but I would never run a 4bl setup on a Z motor.

 

It's just the ethics of it to me... I'd also never put a v8 in my Z...

I like to keep an import.. imported.

just my theory anyway.

-Ed

Heh.. Methinks you are on the wrong web site then.. :twak::lol:

 

Maybe, only time will tell :wink:

Link to comment
Share on other sites

  • Dude has a car with a healthy L6 in it. Good compression and mechanically in great shape but the old SU’s are shot. He buys a 4bbl intake' date=' slaps his favorite type of carb on it and bam! It’s running bitchen. Of course it will compared to a worn out set of SU’s but the advantage goes to the 4bbl in this case. [/font']
  • Same scenario as above except that he gets himself a nice set of Z-Therapy rebuilt SU’s, slaps them on. Advantage SU’s.
  • Another scenario and one that has been brought up before and I think really is what gives the 4bbl a bad rap. Dude has car that runs like crap, engine is just worn out and compression is all over the map, lot’s of factors here that could be causing this but I will just make up one for the sake of argument. He makes adjustments to the stock SU’s to get it to run for the most part. The ability to tune 2 separate banks with the SU’s my even play into this, if let’s say for example 1 or 2 cylinders are way down on compression and they are the 2 near the fire wall then by adjusting that carb he could in theory get the car to run ok… kinda. He gets feed up and convinces himself that the carbs are the problem and goes out and buys a 4bbl setup, slaps it on. I don’t think it will take a PhD to figure out what is going to happen next. Now, he is really PO’ed throws the 4bbl in the trash can and buys some nice rebuilt SU’s, tunes it, car runs better, well of course it does, getting rid of the worn out SU’s should help the situation (but could even make worse in some cases) but having the ability to mask an underlying problem by tweaking the individual carbs is just a cover up, the problem is still there and will need to be addressed.

This is theoretically correct, but I know VERY few people who adjust their SU's independently. Usually it's "turn the nozzles down 3 turns" or whatever. Similarly I know very few people who adjust Mikunis per cylinder.

 

One of my favorite phrases that I hear a lot about SU’s just crack me up “… they are such a simple design and so easy to tune†You have got to be kidding me?

 

What the hell have I been thinking all this time? You are so right, a very old simple designed carb must be far superior to a new modern day type of carburetion. Hell, EFI is so complicated it must be a complete P.O.S. also…. I really wish I could find a carb large enough for my car that uses the same simple design that my lawnmower engine has.

Some people aren't that enthusiastic about rotary engines either. Kinda the same thing. Similarly to the rotary, there are VERY FEW THINGS to adjust on SU's, and very few moving parts, just butterflies, pistons, and needles and seats. But when the new Z owner isn't familiar with anything other than V8's and he goes to tune them and start looking for a power valve it's bound to be confusing.

 

Don't like the lawnmower analogy I used in the earlier thread? Fine. It's the same type of carb used on EVERY HARLEY DAVIDSON until the 90's (or are they still using them???). They were also used on Volvos until the early 80s outside the US. Jaguar and most of the other British car manufactures used them for decades. I'm sure there are MANY other motorcycle carbs that could be cited, in fact I think it would be most motorcycle carbs, I just can't name any others.

 

You make the point that EFI is better. If we're just looking at BETTER, why are you arguing for the 4 barrel? You should be arguing for Motec, or some other hyper expensive EFI that can adjust every cylinder individually.

 

EDIT--As to the carbs being an "OLD" design, how much does it bug the crap outta you when idiots start spouting off the pushrods are OLD technology. Pushrods work fine, so do SU's. A simple design that WORKS is a good design.

Link to comment
Share on other sites

  • Administrators
No thanks. It's a waste of time to keep rehashing the same points without someone doing some testing, I was just defending my earlier points about the SU's.

Sorry if I came off as if I was bashing SU's... that was not what I was trying to do or say.

Rather, no one is really defending the 4bbl setup with any technical data or explanations... just here say for the most part.

And, I did not see your lawnmower post so my use of it was just coencidence.

Link to comment
Share on other sites

SU's are simple any they work. There is a reason why Jags, Lotus, Volvo, Datsun, etc. all used carbs of this design on their inline engines.

 

There is also a reason why every sportbike from day 1 until about 2000 used a variation of the SU design on their inline engines, before switching to EFI. (way after the automotive world) I won't get into the reasons they are pretty self-explanitory and many have allready been mentioned.

 

For balls out performance (which I assume you are after, spending the money to build yourself a stroker) it is hard to beat triple carbs on these engines.

Link to comment
Share on other sites

I dont' want to offend anybody here.. but I would never run a 4bl setup on a Z motor.

 

It's just the ethics of it to me... I'd also never put a v8 in my Z...

I like to keep an import.. imported.

just my theory anyway.

-Ed

 

to super dan and datsun lover, i think the opinion that nismo280zed are allowed in this forum considering we are in the L6 forum,.... its not like we are posting not to drop a v8 in a z in the v8 forum.(keeping in mind this is hybridz) any modification that is not stock is a hybrid of sorts. it really depends on what the driver is looking for. i myself would never put a GM product into my z, while others turn theirs into GM scream machines. if your goin to do it i say go all out, dont mix jap w/ domestic, just doesnt look right.

Link to comment
Share on other sites

Guest norm[T12SDSUD]

You guys need to reread the rules of this forum.

 

You need to stay over at zcar.com or keep the american bashing to yourselves.

 

Your statements are the reason this forum exists as it was an offspring from zcar.com as people got tired of reading anti american rantz like you two have made recently.

 

Later,Norm

Link to comment
Share on other sites

Ok.. first off, I wouldn't go head to head with Superdan about "what should be allowed HERE" even IF it is in the 6cyl forum... For what it's worth, I'm only sticking with my SUs (as oposed to going with triples or a 4bbl) for now because I'm going to go to a V8 next... probly won't be for a few years, hence the reason I just rebuilt the L28; I already had it, and it'll do for now.

 

Your "dont mix jap w/ domestic, just doesnt look right." comment is probly one of the stupidest things I've ever seen posted on this site... No mater WHAT forum it's posted in.. I don't care if that offends you either becasue if it DOES, it only proves the point that perhaps you ARE on the wrong site.

Link to comment
Share on other sites

Can't we all just get along? Come on guys.. seriously. I removed my comment so please do not quote me again. This is sounding a little childish.. I did not bash V8's or even remotely say anything bad about them.

 

Furthermore... we should not be hijacking a thread and wasting bandwidth on this argument. There will be no right or wrong side for an outcome. That is why there is a v8 section and an L6 section.. along with other engines and even 4 bangers. To each is his own. Honestly.. at the end of the day.. if your going to let some comment somebody left on here offend you that much.. than you just let somebody else have more power over you than yourself.

 

(Takes a bow and leaves the thread)

-Ed

Link to comment
Share on other sites

Sure, lets just let anarchy run wild! :lol: The V8 guys can bash stock Z's in their V8 forums, the L6/sr/supra guys can bash V8's in their 6cyl forums, and this site can turn into another zcar.com kinda place.. Lots of ppl with their opinions, but no real info or technical advice. A lot of posts in this thread have good info and real world expiriance, which is a good thing.. I don't think it's wasting too much bandwidth.

 

I'm sorry if I have participated in the 'hijacking' of this thread, but I felt I had to comment..

 

As far as I'm concerned, the addition of the 'what about a 4bbl?' question to this thread is acceptable.. but the thing has gone round and round (a quick search should reveal the recent/infamous 4bbl manifold thread..) and more comments about 'american carbs on jap cars' or 'I wouldn't do...' are not what is needed. If you would never use a 4bbl carb, or an american V8 in your Z, so be it. Why do you have to write a post just to say that? Just my .02$ Ok, I'm done, back to the REAL topic... uh.. triple carbs or not? :lol:

Link to comment
Share on other sites

Guest bastaad525

the whole concept of japanese and american cars is so mixed up nowadays anyways... look at how many japanese manufacturers have plants in the states now, and US companies with cars produced overseas or cars based on japanese or european platforms.

 

I agree there's no place for this "don't put american engines in japanese cars" purism here... take that to zcar.com please. I don't care what engine goes in a Z, if it improves the performance that's all that matters.

Link to comment
Share on other sites

SU's are simple any they work. There is a reason why Jags' date=' Lotus, Volvo, Datsun, etc. all used carbs of this design on their inline engines.

 

There is also a reason why every sportbike from day 1 until about 2000 used a variation of the SU design on their inline engines, before switching to EFI. (way after the automotive world) I won't get into the reasons they are pretty self-explanitory and many have allready been mentioned.

 

For balls out performance (which I assume you are after, spending the money to build yourself a stroker) it is hard to beat triple carbs on these engines.[/quote']

 

Actually, if you look closely, Ford had a VV design in the interim BETWEEN conventional carburetion and TBI.

 

And Honda I KNOW used an SU styled FEEDBACK variable venturi carburettor design. Saw it in the junkyard (dual SU's!) on the Accord I believe, and this was in the 80's.

 

I will say from hundreds of hours looking out the back window of a 69 Corvair with a Single SU Drawthrough Turbo Setup on it, that "tuning" of an SU's fuel delivery is far from easy if you alter from a factory R&D'd needle taper!

 

You start tapering your own needles, and playing with damper springs....

 

BLEYAH! Give me EFI any day!

 

Triple Two-Barrel EFI... Muahahahaha!

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...