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Gordo

Change from triple webers to fuel injection

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Peter raises a good point - a well setup L28 on crabs can be hard to beat even with a good EFI system

Ok folks, I've found the problem.

Don't thanks me all at once now  ;D

Can't wait to get my new Herpes engine running

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I don't know why there is so much emphasis on using ITBs. A well tuned and matched single throttle body system can work very well.

 

Personally I have around $600 (CDN) into my EFI system, using a Delco ECM, and some other donor parts. Which is why I said at the elevated prices in Australia, this should be able to be replicated for around $1200 or so depending on the deals you find. If you went all new parts, then about 50 to 75% more I would say.

 

Before you scoff at this, the Delco ECM has been proven reliable and very suited for performance applications. If you look on delcohacking.net, which is also an Australian based site, there is information about using the ECMs available in Australia, and even custom code to add some functions.

 

My 240 has been running on a Delco ECM for about 3 years now, it was only carbureted for a few months after I bought it. ;) I would do it all over again, even if I was offered a more expensive system. I like the fact that, if I ever needed to, I can find a replacement at a local wreckers, it has a limp home mode, is very easily adaptable, and has on board diagnostics.

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I think Peter and I are coming from a different angle here - my resent zed stuff is all based on track car = carbs at full noice, high HP output engines so fuel economy and driving in traffic is not even in the picture.

 

It has been proven that a single butterfly setup can out flow ITB if sized right for the setup blah blah blah...but if throttle response is what you are looking for then ITB is the direction you go. My mate Ricky's 240z is quick and when we go to run at some meetings people come up to us and ask how well the car goes with a skyline engine in it. They get a shock when we open the bonnet and show them a skyline engine yes a 1960's designed L6 that was used by Nissan in the skyline and zed. There it is in all its old school glory starting at the back of the row sometime from pit lane catching and passing 90's tech including turbo powered cars in the handicap races - and if the run is good making it to 1st with a lap to go :D

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You been Drinkin NZeder, there’s more typo's in your post than in my kids homework.

 

I have considered injection many times but carb's are simple and as the car is driven in the power all the time and tuned to match there wouldn’t be any extra power to be made. Currently we are getting an round 336hp from triple 44 Mikuni’s, if I was looking for economy or wanting to run unleaded fuel then it would be a different story.

 

Cheers

post-967-144023631895_thumb.jpg

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that is on good looking engine Ricky 

efi does make some hp over carbs in the top end , not much but some .the real benefits come from having control over the ignition, this is where i have found lots of hp ..i have done back to back tests with Weber's and efi itb and the carbs held there own it takes a lot to beat them in the top end ..but the efi was much nicer in the tune and made more torque through the mid section also to drive the the car was nicer

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Thanks for the info Peter,

I have add issues with getting a stable ignition setup and last season fitted the Electromotive XDi  programmable ignition which resolved all the issues and delivered more torque, but interestingly no more HP. There are some great features with the XDi like switchable curves and being able to use cranking retard, the current price is less than trying to cobble up your own solution.

 

Cheers

 

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Hey guys...here's my perspective...

 

Carburettors or fuel injection are just mixing devices for adding a quantity of fuel to the air going into the engine, which gets lit by the spark plug, burns up ~20% of the volume in the cylinder (oxygen), while heating up the rest of the volume in the cylinder which doesn't burn (mostly nitrogen), to apply pressure to the top of the piston.

 

The ability to get the right amount of fuel mixed with the air going into the cylinder, and then lighting it at the right moment is the aim of the game. Where the operating range of the engine is limited, the task is relatively easy (NASCAR stock car engines make stacks of power using a single 4 barrel, but operate in a fairly specific rev range). Thru years of development, they have been made to put the right amount of fuel in all 8 cylinders from a single carb. Multiple choke carburettors (Webers, Mikunis) are mostly intended to reduce the vagaries of manifold distribution and all that stuff and allow improved performance over a broader operating range than a single carb (=better driveability). Fuel injection/ignition takes that to the next level, and allows a greater level of control over the entire operating range, and can take into account a great many variables. Fuel injection does not per se produce more power though...that is a function of how much air goes into the engine.

 

Electronic control of the engine provides accuracy in fueling/ignition timing, and therefore may be able to address issues that a carburetted engine cant, thereby giving the impression of more power.

 

So...if it's a race car, you can stay with carbs, tune it for the rev range you need most, make good power, but may need to warm the engine up on hot plugs before putting some cold ones in to race and put up with a few flat spots and that's a pretty cheap way out of it. But....if you want it to start up and drive nice whether it is a hot or cold day and whether you're at sea level or altitude etc etc blah blah, then inject it including ECU controlled ignition, and step into the world of almost infinite tuneability.

 

So...are carbs better than EFI? It all depends what you are trying to achieve. To use the Nascar parallel, injection would do diddly squat for you at Daytona. But if you ran that Nascar at Bathurst, EFI would make it easier to drive and it would use less fuel, and if you wanted to drive that Nascar to work from time to time, then EFI would be the only way to go!!!!

 

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And all this drove the decision I made......

 

No offence to anyone with multiple carbs but in my mind they are too much of a compromise for a dual purpose street/track car so I looked at doing a 6 x ITB L series or RB 25/30 and the numbers just didn't stack up. By the time you bought all the components and then added incidentals and dyno time it was getting out of control. The M3 engine, trans and everything to make it run will probably owe me $8 - 9k, will reliably make over 300 hp (crank) with an excellent torque curve and your grandmother could drive it to the shops. No doubt there are other current generation engines out there that can produce similar results (VQ35) at an attractive cost.

 

David.

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Hey Jamo 240 . thats a good read on what's going on. I have booked my next Dyno not this Sat but the next one so fingers crossed, we have a lot of things to try after all the advice from fellow club members. Thanks Guys.

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Hi guys, I drove the zed today with shorter secondarys, man what a differance it has made. On the short trip to the hwy the plugs stayed clean and it pulled clean down low, it was almost like a differant car. The exaust note had a much louder bark to it from 4000- 5000 rpm, and the driveability was back. I have got a dyno this Sat so I have my fingers crossed.

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I haven't put the step in the exaust yet, might try it at the dyno, it will slip in easy enough. Cheers.

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I do believe that I was the first to bring up the exhaust.

So my dumb a$$ is claiming it  ;D

 

It really does highlight the importance of a good header design though! Most of us have that generic "Genie" type, which is obviously not up to the task.

Good luck with the dyno Gordo

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Hi Garith,  I cut about 450mm off the secondarys , and even though they are of differant length it seams to have helped with part of the problem. the headers are of equle length at 32" long, but finish after the bellhousing at differant lengths about 200mm, therefor the secondarys are of differant lengh. 450mm and 250mm. and merge into the 3". And Simon the exhaust was on my list of to do's, but it is not as easy to do as change jets, ajust cam timing  float level etc, I was just hoping I wasn't going to be a backward step, then I would have had to do it all again. Wayne G was on the money with his theray, and thanks to Peter mac for his help. And happy B'day Pete.

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Thanks Gordon. I also get that bark too between 4-5k.... I have similar length secondaries, mine are twin 60mm and around 400 long then into a cone and 2.5" to muffler then cone out to twin 2.5" all the way through. Good to hear it's all sorted.

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don't be to worried about diffrent length pipes as this will help spread the torque curve, and that loud spot at 4 5000 is a clue that there is turbulence in the port and exhaust at that time ... when i port the L series head the middle ports take lots of work and some times when i test them on the air flow bench if i have made a mistake they will make lots of noise ( turbulence ) and i will have to modify it or it will not work . on Gareth's head it took 3 attempts to get it OK . so there is lot of things going on in a race motor .

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Hi Garith, I'm a little worried about the noise it makes at 4000 -- 5000rpm. how dose your car stack up on the noise meter. I was always close to the 75 db at Sandown, but now I could be over.

 

And thanks Peter, I will let you guys know how the dyno goes. Cheers.

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you guys only have 75db limit over there :( that would be hard to keep to. Hell my road legal with the factory fitted pipe Honda VFR800 is 88DB - 75DB is nuts. Hell new cars from Japan are designed with their laws in mind which is 96DB.....an aftermarket dunny door system from holden 93DB

 

FYI

Here are some common sounds and their decibel ratings:

 

* Near total silence - 0 dB

* A whisper - 15 to 30 dB

* Refrigerator - 40 dB

* Normal conversation - 60 dB

* Dishwasher - 75 dB

* Heavy city traffic or school cafeteria 85 dB

* A lawnmower - 90 dB

* Diesel truck (30 feet) 100 dB

* Personal stereo (ipod) at maximum level - 105 dB

* A car horn, rock concert, or orchestra - 110 dB

* A rock concert, jet engine or siren - 120 dB

* A gunshot, firecracker or jet taking off - 140 dB

* Firecracker or shot gun firing at clos range - 140 to 165 dB

 

So basically you could not mow the lawns at Sandown if 75DB is the rule.

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So basically you could not mow the lawns at Sandown if 75DB is the rule.

 

So thats why they have horses at Sandown.

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I wonder what horses charging down the main straight would rate at..... 75 does seem pretty tight, but some of the cars are LOUD and never seem to get pinged.

 

Gordon, I've never had any warnings I actually think our cars aren't too bad when you hear the Rotary's or the GT40's that also go round. Mine is a bit quieter now as some of that bark was small manifold leaks.... Whoops. I tightened it all up with 1/4 drive rachet and snapped a stud  ::) If it's not one thing it's something else.

 

Keep us posted on the dyno outcome, I'd be interested to see the power your putting out.

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From what I understand the measurement is done at 30 metres from the track, this means your car can be about 104dB at one metre.

 

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Hey N Zeder , I love reading your posts and I might be mowing the laws at Sandown if the zed is over. lol.  Gareth and Salty I to are looking forward to the dyno tune. But Gareth if It makes really good power do I have to tell the Hp, what is club policy on honesty when declaring hp, can it be 10% etherway, I would love to here Simon's comments on this. lol.  Cheers Boys.

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