Jump to content
HybridZ

Triple SU


ArnZ

Recommended Posts

Sad incompatibility!

The end mounts are for the 38MM SU, and the center is for a 45mm SU.

 

Who in the world cuts up a 38mm SSS manifold for such a conversion when the larger units are available?

 

the 510 crowd will howl over that decimation of a vintage part... I know I am.

 

Odd way to go about it for sure!

 

What gets me is 'Super Rare JDM' and then 'Fabricated' being in the advert.

 

The 'nice period modification for your 240' stands out as well. Seems to me period modification was either a 390 Holley, a Turbo Tom's Kit, or Triple Mikuinis...

 

And to think this guy is in Devore, not 20 minutes away. Out of principle I should go find him...

Link to comment
Share on other sites

Sad incompatibility!

The end mounts are for the 38MM SU, and the center is for a 45mm SU.

 

Who in the world cuts up a 38mm SSS manifold for such a conversion when the larger units are available?

It's not impossible to hog those 510 manifolds out to fit Z SU's on them. I know a guy who ran Z SU's on an L20B. Ran pretty good too! That said, it does seem like a backasswards way to get the job done.

Link to comment
Share on other sites

yah WTF!!!!!1!!11!!! I saw it and for a moment my heart leapt.. then I saw the carb flanges and..... ??? I couldn't ID the original manifold, but I smelled something fishy to say the least.

 

Well, I suppose with three EGT sensors you could tune it up OK.. I just cannot imagine what would possess anyone to think to themselves "Gee, I could make myself a triple SU Datsun manifold!!" and then follow that up with, "Well, it just doesn't make sense to use three identical carbs.. what moron would do that?!?"

dee-dee-dee-lg.gifcarlos-mencia-tickets.jpg

Link to comment
Share on other sites

I would be concerned about runner length for the inside carb, It seems to be twice as long as the outside. If the welding is as bad on the inside as the outside looks it will not flow very well. I have a Manifold also but it was made of original ones with the inside runners cut off and sealed and then the runners mounted to a new carb flange.

full view top_thumb.JPG

full view front_thumb.JPG

Ballance and linkage 1000_thumb.JPG

Link to comment
Share on other sites

When I first started my lust for a unique intake for my car I figured a triple SU would be cool. I then learned the Z Therapy had already made one and had a video on you tube. I called out there and talked to them about making the patterns for them. They said that they had already secured a pattern maker to produce the patterns. That's when I started looking for something else to make and the rest is history... or at least in a few weeks it should be history. All and all I'm glad it turned out the way it did!

 

Derek

Link to comment
Share on other sites

back-to-zcars, that is a very nice manifold you have there!

 

I have two spare manifolds and access to a full welding shop...

hmmm

I'm smelling another project as soon as I get my current car running!

 

Derek, how long ago did you contact them about making their patterns for them? It would have to be more than a year ago, right?

Any word on the status of their product?

Link to comment
Share on other sites

Thanks Cockerstar. The real nice thing about it is the outside carbs are at the same distance apart as the original set up. I am planning on cutting a hole in the center of the air cleaner base, and mounting the original air cleaner on the triples.

 

Sweet, stealth triples! I guess I'm just a youngster, but that "remote bowl" setup on the center carb is kinda wild.... is that typical, or would most OEM applications have the carbs spaced more "normally?" I see things that I would do differently, but I think the second manifold posted is niiiiiiiice........

Link to comment
Share on other sites

Daeron, I am sure this is not a typical set up all custom. Healeys and Jags came OEM with triple Su's and they were spaced to allow for the floats in the normal placement. I had a triple carb 240 built like this in the early 80's that I am not sure how I am still alive with how I drove it. I am not sure if this is the same manifold that I used to own, but like you said it will be a sweet stealth triple Su L28 by the spring time.

Link to comment
Share on other sites

I remember reading an article years ago written by this one guy who did some investigation into the inner workings of such a setup. Shame I don't have that article to re-read. In a nutshell, it was a setup that was prone to problems based on the firing order and carb groupings.

 

Su's apparently run the best when the pulses through the manifold are at even intervals. A manifold such as this doesn't allow for this beneficial effect to occur.

 

And if I remember correctly it could work if the cylinders were grouped differently. Again, something to do with the number of degrees of crank rotation/firing order sequence.

Link to comment
Share on other sites

I gave the seller a heads up on what the manifold really was, but didn't want to be taking credit for the knowledge so I gave him a link. Here's what he had to say about the whole ordeal. Thought you guys might like to know ;)

 

 

Sad that the poor fellow who created this Frankenstein, whoever he may be, will most likely never see the lovely, complimentary words from those visionaries on that web-group. I found this weighing down a box of other parts that I purchased and listed it for sale with mild amusement to see what it'll fetch. The true irony is that at least one of the outspoken clan on that list will be bidding on it with some clandestine pseudo-ebay name that none of their "friends" knows about! Thanks for brightening an otherwise dull day. Oh, and perhaps the chap who wants to come see me "out of principle" should realize that it was a Z guy (like him) who made this, not me. Nonetheless, he's welcome to come see me, I haven't had a good laugh in a while!

 

Cheers!

 

PS. Feel free to add this to the list.

Link to comment
Share on other sites

Just because someone is a "Z-Guy" doesn't at the same time preclued the fact he may be a total idiot.

 

THe "Principle" I was referring to was his blatant lie about the parts being "RARE JDM"---that's a full crock of B.S. and I'll stand by it.

 

Too bad I'm in Morocco now, I hate lying hucksters that use puffery to take in the ignorant. Apparently he finds nothing wrong with his description of the item. That's really sad. But anything to make a buck, huh? Whatever you got to do to move the iron.

 

Since you gave him a 'heads up' and he's not changed the ad one iota, I guess that informed consent is not on his list of priorities to prospective clients. Welcome to e-bay.

Link to comment
Share on other sites

I agree with you about him not editing the listing!

I wasn't wanting to bring conflict up about you wanting to talk to him about it, just wanting the conversation about his item to be available to him so he could learn a bit about what he has. I didn't want to be that guy who just tells you that there's a mistake in your listing without a real explanation of the reasons behind the errors.

Link to comment
Share on other sites

I remember reading an article years ago written by this one guy who did some investigation into the inner workings of such a setup. Shame I don't have that article to re-read. In a nutshell, it was a setup that was prone to problems based on the firing order and carb groupings.

 

Su's apparently run the best when the pulses through the manifold are at even intervals. A manifold such as this doesn't allow for this beneficial effect to occur.

 

And if I remember correctly it could work if the cylinders were grouped differently. Again, something to do with the number of degrees of crank rotation/firing order sequence.

 

The article you read is probably from Marc Sayer and is total BS. ZTherapy built a prototype 3 SU setup to see if it would work and it works quite well. I had it on the engine I used to use on my autox car. When I ran it I had two huffaker modified SUs that created great top end but were like a light switch (on or off -- no in between).

 

When I got to sample the same engine with the tripples I couldn't believe it was the same engine. It had a much smoother power delivery and a lot better mid-range. I've also tried the same engine with real 50mm SUs and the power delivery wasn't as smooth but top end power was the same.

 

To get the pattern made for the manifold was fairly expensive and there wasn't a ton of interest. So it may be a while before you see those available. And this won't be cheap.

 

Cary

Link to comment
Share on other sites

The article you read is probably from Marc Sayer and is total BS.

 

I don't know about the article referenced or Marc Sayer's article, but I was part of some testing done by Javier at JG Engine Dynamics back in the late 1990s. The intent was to build the best autocross BSP 2.8 possible given the rules limitations and triple SUs were tried along with dual SUs, triple Mikunis, and aftermarket stand-along EFI.

 

The order of performance (max HP and Torque) was:

 

1. Stand alone EFI (ITBs and Electromotive Tec2).

2. Triple Mikunis (45mm).

3. Dual SUs (44mm).

4. Triple SUs (44mm on modified N36 manifolds).

5. Dual SUs (50mm on modified N36 manifolds).

 

The fastest BSP 240Zs in the country ran either EFI, Triple Mikunis (Webers), or Dual SUs. I don't know of anyone winning a Divisional or a National event with triple SUs. I don't know of a road racing 240Z running triple SUs, mostly because of classing rules in SCCA.

 

Triple SUs might be a good setup, but the racers are not running 'em - probably because they are about the same price as triple Mikunis/Webers once all the fab and linkage work is done.

 

EDIT: I called someone else who was at the testing to refresh my memory. The issue with the triple SUs was that cylinders 3 and 4 ran lean compared to the other cylinders (based on EGT and spark plug reads). Later they shined a strobe light down the middle SU at various rpms and noticed the piston fluttering up and down while the outer two SUs had the piston rock solid.

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...