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EFI vs. Triple webers


Guest crawfoth

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Guest crawfoth

Recently I come across a guy with a set of triple webers on his Z. I have heard about them before, but this is the first time I had seen a set. I must say, the apperance of the three of them when you pop the hood is impresive. Now what my question is. Is it possible to transfer an 80 280 from EFI to triple webers. If it is, what would be involved other than changing the intake, tweeking the carbs, and figuring out the throttle linkage? Next question is, what are your opinions on EFI vs. Carbs. Is there any benifit in doing this swap other than the aww effect when I raise the hood?

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Guest JAMIE T

I would think low end throttle response would suffer, but top end would be stronger. Tuning is said to be a PITA. Cold starting may suffer as well. But, I know some guys who love Webers. Pretty costly also, expect to pay about $500 for a used set with intake and linkage. That is on the cheap end, more likely to be $700 for a perfect used set. Over a $1000 new. I think if you wanted to, you could build(or have built for you) a nice looking EFI intake, that would get nearly the attention that the Webers would.

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Most tripple setups dont have chokes. It might offer more "tunability" than EFI, but EFI is known to produce more TQ across the range than carbs, this may though be due to poor setup, and/or maybe just poorer atomization. Once you start adjusting carbs it can be tough to maintain an even AF across the board, and to achieve it you will have to change more than just jets, because the linearity of the carb will be ruined when straying from factory specs, so air tubes etc must be swapped also for best results.

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The triple Webers/Mikunis look great, sound great, and make good power. But they tend to be a pain in the ass to get setup correctly. FI, particularly the programmable setups like SDS, Haltech, Electromotive, DTA, and Motec are easier to setup and will ultimately produce more horsepower and torque.

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Triples are great and you can tune them however you and your budget desires. A simple choke swap can turn a high strung engine into a torquey one, and vice versa.

 

They are much more versitile then the stock efi, and you can make a lot more power with them, biut they don't get the MPG an efi gets. Throttle response is better, and they sound incredible.

 

I never had cold starting issue's with mine, and I could get you very close to spot on as far as jetting and such goes. I would like to have a set of them again, but I have moved into turbo's.

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Guest vodkaboy

it will probably easily frustrate you tuning 3 carbs, webers no less. then again, EFI is also frustrating, when it decides to randomly not work. kinda comes down to this: what do you know how to work with better; L-Jet fuel injection, or a mess of carbs?

 

another thing to think about is smog laws in your area: are you allowed to step back from EFI to carbs?

 

either carb or EFI can get quite expensive... 6 injectors is $450, when my ECU fried it was another $450, and the constant torment of not being able to tune it and asking what is wrong with it... then again, 3 webers is also quite a handsome sum of money, and i doubt would be the easiest setup to tune unless you are a guro of such carbs.

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Triples are not hard to tune IF you understand how the carbs work.

When they are tuned correctly, they give very good performance and driveiblity.

You can set/ajust them to your engines needs.

I ajust my linkage and snyc my webers 2 or 3 times a year.(minor ajustments)

I do not have any choke cables installed and never have problems starting the car, even in winter.

 

The best thing about them is the sweet sound they make sucking all that air in! :D

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I agree with DCarrow. Be careful with the terminology above:

 

Most triple setups DO have conventional enrichment chokes for cold start, they just don't work very well usually and are not hooked up by most people. However, in most climates they are not needed since they have accelerator pumps. Just mash the throttle two or three times, then turn the key. Once it fires up, usually keeping it running for 30 seconds or so with the throttle will allow it to idle on its own. The SUs found on 240s DO require a choke for cold start on cool/cold days because they have no accelerator pump.

 

The side draft carbs have interchangeable venturi sleeves. These are called "chokes" as well. They are another tuning device for these infinitely adjustable fuel mixers, but they are not a cold start enrichment feature and are NOT optional.

 

http://www.motorbooks.com has books on Weber and Del'Lorto carburetors and one book that covers both. Highly recommended for your edification regardless of whether you choose the triple route.

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Side drafts are intimidating if you let them intimidate you. Getting them right is not hard, trust me if I can do it, so can you.

 

If you like the aww effect, try having a set on a nice high compression engine with a big cam and hammering it. That is you aww effect right there. Nothing sounds sweeter to my ears.

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If your motor is stock (no head work, etc.), then going with triples will not gain you anything, except a maintenance item. If you want the look and sound, then that's another thing. I've seen triples in a 280ZX, so it is easily done. The car was slow as a dog on the 1/4 mile (not sure why). It go beat bad by a stock 280Z.

 

To me, if it doesn't improve performance, it's not going on my car. If it looks cool and improve performance, BONUS!

 

Spend the $700 bucks on a programmable fuel computer. Yea it won't be a sexy as the triples, but you will have the tunability, and drivability of EFI. Your gas mileage won't suffer either.

 

Pete

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it will probably easily frustrate you tuning 3 carbs' date=' webers no less. then again, EFI is also frustrating, when it decides to randomly not work. kinda comes down to this: what do you know how to work with better; L-Jet fuel injection, or a mess of carbs?

 

another thing to think about is smog laws in your area: are you allowed to step back from EFI to carbs?

 

either carb or EFI can get quite expensive... 6 injectors is $450, when my ECU fried it was another $450, and the constant torment of not being able to tune it and asking what is wrong with it... then again, 3 webers is also quite a handsome sum of money, and i doubt would be the easiest setup to tune unless you are a guro of such carbs.[/quote']

 

Don't know where you get your injectors and ECUs...My stock turbo injectors cost $120 new (set of 6), ran them for 2 years. My new set of 370cc injectors I bought for $7 each at a scrapyard - I bought enough of them to flow test and pick 6 good ones, so they cost me about $100. And ECUs are cheap if you cruise eBay. I bought my latest ECU for $70, and you can find them cheaper on Zcar.com classifieds too -- I bought 2 ECUs and a MAF for $100 there. If you are into tweeking and DIY, EFI can be just as economical as carbs, maybe more so if you don't have to spring for a ~$800 (I don't know how much they run) set of triples.

 

You just can't beat the driveability of EFI, but I agree, a set of triples on an L28 is a thing of beauty.

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Even on a stock engine, sidedrafts will outperform stock EFI. YOu have individual venturies for each cylinder.

 

Likley the car had F16 emulsion tubes in it rather the F11's, which made a huge difference on my car. It could have also had little chokes, could have been jetted improperly, etc.

 

When my 240 was stock except for a header and sidedrafts, a 280Z EFI could hang with me thru first and second, and then I would eat its lunch. EFI just does not deliver the airflow to the engine sidedrafts can.

 

The key is properly tuned.

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Well do some simple math. Take one 33 mm hole, and multiply that by 6. The compare that to the single 51 mm hole in the stock TB. Which do you think flows more air?

 

Plus you don't have that dumb door on the nissan afm in the way either.

 

If you had ever driven a car with sidedrafts you would know what I am saying, they rock when they are dialed in. Its just that most people never take the time to do it right. Once dialed in they are low maintenance items, and they actually meter fuel very precisely. Not as precise as EFI, but certainly much better then a holley.

 

If I had a set, I would prove it to you, but alas I have moved on to forced induction. I used to have a set, and can tell you with all certainty, they will outperform stock nissan EFI. Anyday.

 

And if you plan on adding a cam and header, well it just gets better with sidedrafts. And the sound, pure music. They have very sharp response.

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If I had a set' date=' I would prove it to you, but alas I have moved on to forced induction. I used to have a set, and can tell you with all certainty, they will outperform stock nissan EFI. Anyday.

.[/quote']

 

Can "stock Nissan EFI" also include the Z31? The MAF is about as non-restrictive as a factory ECU gets, at 2.75" ID. That is 70mm, bigger than the throttle body. And for passing flow upwards of ?400? cfm on an N/A 2.8 or 3.1 liter, how much pressure drop are we talking? 1"? 2" of Hg? I think with the Z31 system and a reasonable throttle body (60mm) there isn't a whole lot of WOT the system is lacking with EFI.

 

No numbers, and I know you've got the experience where I don't, just my thoughts.

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Plus you don't have that dumb door on the nissan afm in the way either.

 

AFM doesn't get used with an aftermarket setup, and since the stock setup + work is fairly limited, big HP guys are not going to use it, so no AFM. As for the MAF, yeah people complain about that and the little TB on the LT1s too, but they are running 9s in the quarter, so I think the MAF argument, especially boosted is a bunch of hooey.

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