Change from triple webers to fuel injection
Posted 01 June 2011 - 10:00 PM
Posted 02 June 2011 - 10:06 AM
You know all this stuffing around and tune ups have probably cost you over $5,000- over the last 10 years anyway. Sometimes you have to spend money to save it dude.
Posted 02 June 2011 - 11:53 AM
Even at the elevated Australian prices I'd say it's possible to go EFI for around $1200, or so. Being a little innovative wouldn't hurt to help keep the costs down.
Posted 02 June 2011 - 02:12 PM
Posted 02 June 2011 - 09:45 PM
can you give us an idea of what you can get for $1200
Even at the elevated Australian prices I'd say it's possible to go EFI for around $1200, or so
Posted 02 June 2011 - 10:08 PM
Posted 03 June 2011 - 09:10 AM
Posted 03 June 2011 - 09:34 AM
Posted 03 June 2011 - 10:02 AM
Posted 03 June 2011 - 12:54 PM
The point if you had a clear sheet of paper and had to purchase either EFI or Carbs from new both are going to cost a good amount of coin to get right. ie Carbs $1500, number of jets/chokes if you don't have a close starting point or a carb guy that can lend jets/chokes to get it right on your engine upto $500-1000 and dyno time $500-1000.
Other items on the engine should be the same, headers, engine build etc. So for Carbs from $2000-3500 - again assumes all new parts
Now EFI - good ITB $2000-2700, good ECU $1000-2000, injectors $500-700 - again assume headers,engine and fuel system up the EFI job these will be extra if you need to upgrade from low press to high press system and then dyno time too $500-1000
So EFI cost $4000-6400.
Peter raises a good point - a well setup L28 on crabs can be hard to bet even with a good EFI system (ok a great EFI system might be better) but a great EFI setup is going to cost a lot of coin. If I had mine time again for the power goals of my engine (even though it is a RB) I should have stuck with carbs would have been cheaper and also very different too. I know the reasons for going EFI as those are some of the same reason I decided to go down this path ie more liveable as a road car, easy of having 2 maps (mild for the road and more free for the track). At times I think I should have stuck with carbs for my NA RB powered car that way I would not had required fuel system upgrades, injectors, ECUs etc - I could have just got a good crank trigger ignition setup and stuck with carbs and the car would be perfect like that for 1/2 the cost.
Posted 03 June 2011 - 01:25 PM
Ok folks, I've found the problem.
Peter raises a good point - a well setup L28 on crabs can be hard to beat even with a good EFI system
Don't thanks me all at once now
Can't wait to get my new Herpes engine running
Posted 03 June 2011 - 01:56 PM
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.
Posted 03 June 2011 - 02:25 PM
Posted 03 June 2011 - 02:39 PM
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
Posted 03 June 2011 - 06:19 PM
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.
Posted 03 June 2011 - 06:56 PM
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
Posted 03 June 2011 - 07:20 PM
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.
Posted 03 June 2011 - 10:24 PM
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!!!!
Posted 03 June 2011 - 10:45 PM
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.
Posted 09 June 2011 - 05:53 PM
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