Carb replacement

[Tophu530]

Hey so I don't know that much about cars so don't kill me if this Q is dumb.
I was wondering what the benefits of switching out my SUs with triple weber carbs. What are advantages and disadvantages. any help would be great thx.

[yetterben]

Fuel economy goes down the tank if setup for performance. Top end increase in power is the reward. Triples will always look and sound better than SU's. The purist people will yell and scream but no denying datto themselves used mikunis in there market.........

[Bruce Palmer]

If you're anywhere close to Salem I'd invite you to come by the shop and experience what a correctly done set of SUs can feel like. You can take it from there.
I'm waiting to see if anyone responds about the costs involved to get those triples dialed in...... Bueller........ anyone........ Hmmmm.

[Zs-ondabrain]

Decent set of triples with Manifold and linkage....... $1500 average
Rebuilt Set from ZTherapy, bolted to your stock manifold and linkage...... $630 + Core ( Core is $150 if you don't send them yours)

SU's... Barely any Tuning
Triples... Tuning X3. Wide band O2 meter, Dyno Tuning is better for peak performance, etc, etc..... I'll let Yetterben fill ya in on the specifics.

If the Triples were used and off a well tuned motor (already tuned and ready to go) then you're in luck.

Just go with the SU's. BEST damn thing I ever did to my 70' 240Z. Thanks Bruce and Steve.

Dave

[LeonV]

SUs are great, but everything comes with its pros and cons. The SUs are easy to play with as long as the throttle shafts don't leak, but they leave some performance and tunability on the table. The Webers are more expensive, but you can tune them in much more detail. This assumes that one understands both systems well.

I got a decent set of Weber triples for $600 complete including manifold and linkage. The deals are out there if you explore classifieds enough. I've seen quite a few recently in that price range, in varying condition.

Also, don't slap parts on without thinking. You need to think about what you need in terms of what the car will be used for.

[yetterben]

Triples will always be better why.......endless tuning possibilities. I have driven in a car with hogged out SU's that where properly tuned and they do drive good. But they dont offer the hammer of god sound triples do when at wot. Let alone the crescendo you hit at 5 grand. Let alone dogs and people running from the car as you drive buy....i could go on. Triples are just plane fun.

I'm waiting to see if anyone responds about the costs involved to get those triples dialed in...... Bueller........ anyone........ Hmmmm.


Yes if you have no real base line it can get spendy. But most of the guys out there with 700-1000 in jets etc could have saved themselves loads of money and time buy getting a wb02.

But if you are using cost to to say Su's are a better choice that's like comparing a yugo and a 240

You cant negate the fact that the factory used what in its racing teams? So for balls to the wall power choose wisely. No way a set of su's can even be the same as 6 34mm gaping holes into the valves. Just not gonna happen from flow characteristics alone.


I will add that if you are a lathe master an can turn your own needles SU's could be dialed in really well i suppose.

Bruce has a good product but like anything it has its limits.

In summery you need to decide what your car is for if its for dd and occasional abuse get the su's If its for track use or heavy high speed use triples. Su's don't belong on the track or in competition unless its a spec vintage class.

As far as the track is concerned bring the su's on over to road America and lets put it to the test.

[Bruce Palmer]

Road America 2010 Runoffs E Production Z #82 will be there this fall with SUs. Check it out.

In fact this car has a double national in Portland this coming weekend.

[yetterben]

Bruce i will be there that weekend as well. But like i said its required he have them.....its a production class. I really love that you guys mod the Su's but can you say you can outflow the triples. What about intake design. Cannon, Mikuni, Datto comp, FET, Kameri etc.....


I will add this to this thread. Any stock l series inline 6 here yah go for a baseline. F11 e tubes 55f9 idles 135-140 mains 190-210 air correctors. 0 bleed back in pump jet well. 4.5 aux venturi's 200 needle. Mains and correctors vary on choke size.

[Bruce Palmer]

I guess I see those 2 Hitachis powering the race car down the front straight at Portland at around 140 mph and wonder how many daily driver types are going to see the sunny side of that. That's, give or take, 8 grand.

"I drive 11/10ths all the time" is what I hear some guys trying to float. Then again our basic customer will own up to something a little more realistic in terms of the trip to the grocery store maybe isn't a timed event........

Without forced induction of some sort, SUs, Webers, Hollys, etc are only going to supply as much air and fuel as the engine is going to draw..... The infernal combustion engine is afterall nothing more than an air pump.

Cheers

[yetterben]

Point taken. Its a personal preference and i just happen to be in the triple camp is all. Nothing wrong with your product.

[Jeff G 78]

Hey so I don't know that much about cars...

Based on the first line of the OP's question, there is NO WAY I'd recommend triples. They sound fantastic and can be made to run great, but they are magnitudes harder to tune than SUs even for the experts. Do yourself a favor and take Bruce up on his invitation to visit his shop. Spend the money and take home a set of his beautiful SUs. You'll be very happy.

[yetterben]

I must have missed that. Indeed triples are not for the faint of heart. Sounds like bruce's SU's is your bag of fun waiting to happen. Enjoy the car, when you start to feel the need for never ending screw turning get some webers.

[LeonV]

Without forced induction of some sort, SUs, Webers, Hollys, etc are only going to supply as much air and fuel as the engine is going to draw..... The infernal combustion engine is afterall nothing more than an air pump.

Are you trying to imply that SUs are able to optimally feed each cylinder? The manifold design for SUs has been proven to be flawed in terms of mixture distribution to each cylinder with WB02 data-logging. The AFR between cylinders is not consistent, and there are some nice bends in there as well adding more pumping losses.

On the other hand, a triple setup gives each cylinder its own venturi. Bends in the intake tract are minimized and the mixture cylinder-to-cylinder is more or less consistent. It is also possible to do effective intake resonance tuning with this setup by simply switching out bell-mouths.

Yes, SUs work well and are great for someone looking for street driving and decent performance. However, when it comes down to tuning and maximization of power (or efficiency), the Webers have a profound advantage.

Yetterben brought up a good point in that the EP racers need to keep the stock carbs. You think that if carb choice were unlimited that SUs would be preferred over Webers? I think not.

As for the OP, if you don't know a lot about cars don't even think about triples, unless your wallet feels too heavy.

[yetterben]

This has been documented. I did not wanna bring this up either as this war never ends the little skirmish battles get won but no one can ever agree.

I stand buy my 34mm x6 theory. I also stand buy unlimited tune ability.

In this case though the OP sounds like he needs hassle free driving.

As far as pricing though. I want to make clear unless you are buying triples new (webers anyway) they are not worth 1500. USed webers are worth about 100-125 a pop unless there is documentation to back up a rebuild. Or how long they have sat. Why webers have dropped in price...loads. One can get a new carb for 275 bucks now. I learned instead if buying floats and needle jets to just buy the whole top cover for 70 bucks. Gets you 90 percent of a rebuild brand new float brand new shiny cover bolts etc.

Intakes are a different bag. I think the cannon/pierce mani is kinda junky. The two i have had where very rough, casting flash was really bad. the mikuni mani i had was top notch. The kamereri intake is very very very nice. for 450 bucks you get a super sweet intake throttle linkage the works.


Oer is still being made and qulaity has stepped upped. They are setup to handle boost as well up to 15psi. I almost went this route when i had my hks blowthrough setup,But at 550 a pop thats alot of cash-olo


I think what ultimately needs to happen is a dyno shoot out with the same car and different induction setups. From a non biased person at a location yet to be chosen lol.

I just wanted to put it out there that these carbs are not worth 1,500 and surely run from msa setup. The people i have talked to lately say they have been getting mix matched carbs and jet setups.

Mikuni and all the other carbs mileage is gonna vary. Some cost more than others. Webers are the ultimate in tune-ability. But there is something to be said over the mikunis or even the oer/sk rip offs of mikuni for a time piece.

[LeonV]

I agree about the pricing as well, $1500 is ridiculous! Might as well go standalone FI at that point. I think that $500 to $800 is more like it for a complete triple setup, depending on condition of course.

I was actually planning to go dyno testing with well sorted SUs vs. Weber 40mm triples when my Z is back on the road. I have both setups and am curious as to the quantitative difference between them.

[Zs-ondabrain]

Well, There's a 1/4 mile shoot-out coming up on the 18th and I'd love to have the triples (Weber 40DCOE's) rebuilt and tuned by then. Then.... Make a few runs on the SU's, then take 40 minutes and swap in the Webers, linkage and timing and make 3 runs on those.

Post the results and let the conversation fly. This way, it'll be the same car, same motor, and same driver. I love my new SU's but also love a well tuned set of triples. I can say it will be a non biased test as I'll be happy to just be able to run the quarters, no matter what's under the hood or feeding the motor.

We'll see.
Dave