Jump to content
HybridZ

Custom L24 intake


gjc5500

Recommended Posts

I was planing on making a custom intake for my L24 in welding. i know that tuned headers have equal length runners to alow for better scavanging, is the true with intakes aswell? will 6 equal length runners preform better? i plan on making this for the Weber DGV carbs since the manifold that came with them suck. does anyone have the dimensions of the intake flange for the E88 head? that would help since my Z is my daily driver. What thickness should the flange be, and what piping should i use for the runners?

Link to comment
Share on other sites

I would not bother with the webers. If I was building as custom manifold it would be using tripple stock 240 SUs. One thing really watch the heat distortion when you start welding. I would start with a spare head or jig and build off of that.

 

Have fun, welders do there best work in the dark!

Link to comment
Share on other sites

The problem with the Webers is that you'll need to have them mounted higher than the hood in order to make a manifold that doesn't do that question mark shape, and that is the part that makes the Cannon manifold suck so bad. Maybe try to find a side draft carb to adapt that you can make your manifold for, or make a header instead.

Link to comment
Share on other sites

  • Administrators

Sorry for the way off topic, but I couldn't resist...

 

I don't think he'll mind, so here's some triple-SU candy for you, built by Steve Epperly (ZTherapy)...

.

trippSus.jpg

.

In my opinion, there are many welding projects that you could perform on your Z... the Weber's are a large waste of your time.

Link to comment
Share on other sites

There was a discussion some time ago about the triple SU setup, and a problem that was discussed was the fact that the firing order of the L-series doesn't work that well with it.

 

Basically, the carbs see the following:

 

Carb 1 sees the 1st and 5th cylinders in the firing sequence

Carb 2 sees the 3rd and 6th cylinders in the firing sequence

Carb 3 sees the 2nd and 4th cylinders in the firing sequence

 

So, while the middle carb's events are evenly spaced, the outer two are only separated by 1 event with 3 events in between.

Link to comment
Share on other sites

  • Administrators
There was a discussion some time ago about the triple SU setup, and a problem that was discussed was the fact that the firing order of the L-series doesn't work that well with it.

 

I may be speaking out of turn, but the impression I got was that it was largely done for wow factor.

Link to comment
Share on other sites

In my opinion, there are many welding projects that you could perform on your Z... the Weber's are a large waste of your time.

 

I agree there is just to many neat projects, strut bars, a custom rear end panel, suspension parts just to name a few. Look at some of the stuff that other people have fabricated for ideas.

Link to comment
Share on other sites

I may be speaking out of turn, but the impression I got was that it was largely done for wow factor.

 

FWIW, I have personally ridden in Steve's car and it runs as well as it looks. It is an L28 with a huge cam. It's sounds like a built V8 at idle. For an N/A car it really pulls hard. I'm not knowledgeable about SU's but the car seemed to drive and start perfectly.

Link to comment
Share on other sites

why would it have to be higher than the hood? Why couldnt it be like the 4bbl manifold where it makes a slight upward slope? i would LOVE to have tripple SUs but i have -400$ rite now and no job. i just need a project.

You have a point, I may be wrong. I seem to remember people running extremely thin air filters with the Weber and 4bbl setups, and hearing that hood clearance is an issue. Looking at AZC's website it looks as though a 2" air cleaner fits under a stock hood unless you have a '77 or '78.

Link to comment
Share on other sites

I woudl love to get tripple SUs but have no money for them. I just need a project for a wedling class im taking. i figured making a better intake for the webbers would be a good project.

 

why not make a new crossmember for the car with some adjustable links.

 

heck if i had to do that for school, then i'd be all over that day and night.

Link to comment
Share on other sites

There was a discussion some time ago about the triple SU setup, and a problem that was discussed was the fact that the firing order of the L-series doesn't work that well with it.

 

And I can tell you from personal experience, having driven the car, that it's totally wrong. The engine in Steve's car is my old race motor that used to run two highly-modified SUs. In that configuration the car pulled okay from about 2500 and started to come alive after you crossed 3000 on up to my rev limit of 7500.

 

Running the tripples I was able to give the car full throttle at 1200 and it took off and started pulling really well once past 2500 on up to 7500. What amazed me was the car was much more driveable than it had been with two carbs in my old car. And in Steve's street car, which is probably 500 pounds heavier than my race car, it pulled every bit as strong.

 

Steve built the tripples because he always thought they'd work and wanted to see if it would. If you ever get a chance to see the car in person you'll see a lot of really nice detail on them. All the stickers appear to be factory and show the three carbs, etc.

 

If you're looking for a welding project this would be a good one.

 

Cary

Link to comment
Share on other sites

  • Administrators

Hmmm… The firing order theory sounds like it might have some merit in theory and possibly worth investigating. As counter point, the 4 cylinder SSS Blue birds (aka JDM 510’s with L-series 4 cylinders), run dual SU’s and because of the of 1-3-4-2 firing order, they would also suffer from the same issue, but they seem to run fine. Also having seen Steves Triple SU car run in person, talked directly with Steve about his Triple SU’s, and also talked to a few people that have driven and rode in the car, if there is an issue with the firing order affecting the operation of the Triple SU set up, apparently those alleged issues haven’t shown themselves, or at least are quite minimal if present at all, as the car runs very smooth, for an N/A L-series, makes GOBS of power everywhere and gets decent freeway mileage, (city mileage wasn’t great). I don’t recall the exact mileage numbers Steve quoted on his trip from the middle of Oregon to the MSA show in Cali this last year with that set up, but I do remember the mileage being respectable for how radical the engine is built up.

 

Just my $.02 on the Triple SU set up…

Link to comment
Share on other sites

Cary and Paul, I've had the same argument with a more than one person who claimed the triple SU wouldn't work also.

They always wanted to argue about the firing order as well, but none of them could explain how a triple Weber/Mikuni/ etc set up could work so well and not a triple SU set up. If their theory was correct, then wouldn't it stand to reason that the center carb of a triple Mik/Solex/Weber would have to be jetted substantially different than the other two? Of course, when I would bring that point up, they always backed down a notch. I always contended that with a balance tube (which Steve has) it negates a lot of their theoretical problems with the SU set up.

I talked to Bruce at ZT and he sent me a couple pics of Steve's work just before he finished it and I have to say I love the fact he made it look like it was an OEM piece.

 

I have a triple SU handmade manifold that I plan to experiment with also whenever the money for some modifications is in my hands, there is no crossover or balance tube so until I get that fabbed up and welded in, it's going to sit in a box on the shelf.

Link to comment
Share on other sites

If their theory was correct, then wouldn't it stand to reason that the center carb of a triple Mik/Solex/Weber would have to be jetted substantially different than the other two? Of course, when I would bring that point up, they always backed down a notch. I always contended that with a balance tube (which Steve has) it negates a lot of their theoretical problems with the SU set up.

 

I think you're right about the balancetube helping a lot. I added a balance system to our tripple weber setup years ago and it definitely helped the mid-range. I used some parker fitting for air brakes. They have a special small diameter pushlock hose that's easy to work with. One idea to speed along your project until you have time to fab a balance tube.

 

Cary

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...