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Gordo

Change from triple webers to fuel injection

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Hi guys, I'm just about over trying to tune my L28 triple 45 Weber's. On the dyno idle is OK , progression is lean and top end is OK. But on the road it is all ways fouling plugs. If we change emulsion tubes to get the mid range good ,the top end is to rich, just going around in circles. What ever we do can't get a good power curve. But at the end of the day it still fouls plugs and then its undriveable. The cam has 480 thou lift and the extractors are 32" tuned length primerys 1' and 5/8 diam. The Weber's had 42mm ventures and tryed 38mm but no change. it's got me to the point of exploring the options of going to fuel injection, how much would it cost to set up  fuel injection, and would it be worth changing over ? Cheers Gordon.

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I havent spoken to Peter yet, but he would be first on the list if I choose to take the Injection option.

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Hi gordo,

EFI is the way to go with full control of the ignition, as most l28 with your combo will have a dip in power around 4000rpm and will run very rich in this spot and is very hard to tune around with carbs.

If you need help to go efi i can help with the parts and the tune, the only problem with efi is the initial cost to set up.

 

EFI cost

I like to use Haltech and you will need a full sequential computer to get it to run the way you need it to this will be around $2200.

Distributor cost with home and trigger around $600.

6 X LS1 coils around $50 each.

EFI hardware individual tapered throttle bodies size 48/45/43 cost ???? best to call EFI hardware and check price.

You can use your Weber manifold to save some money.

6 X Injectors all up roughly $500.

Fuel pump high and low pressure and surge tank will be around $600.

Fuel line and clamps roughly $50

Installation of parts cost will vary depending on if you can do some yourself or have it all done for you.

Tuning will mean the car will be on the dyno most of a day so you will be charged per hr at around $100 an hr.

 

Any questions just give me a call.

 

Thanx Pete!

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  Thanks for all that info Peter, It will be worth looking in to. As I keep throwing money at this thing and not getting anywhere,I may start to collect the efi hardware. Thanks again Peter. Regards Gordon.

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Hey Gordon, If its fouling plugs to the point of causing an engine miss, there is something lurking in there you maybe overlooking, if its running rich you need to know how rich in air/fuel mixture ratio it is , it may not even be the carbs, when was the last time the needles and seats were repaced?

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Gordon

 

Junk the Webers and install a set of Mikuni's !

 

I know of a set of Triple 44's for sale that were running on my old 240z Sc race car (turning 145 rwkw from a little L24 !)

 

The Mikinu's are complete with linkages, manifold and 50 mm ram tubes...................and ready to bolt on

 

Once dyno tuned properly you won't need to touch them again

 

I think the asking price is around $2500

 

PM me if you are interested

 

Alan

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Gordo you want reliability. You have a fast car but need drivability and like you say. You can waste a lot of cash on tuning carbs and still never get it right. You race the car regularly and have done for 15 years, probably more.

So go for the fuel injection. You won't regret it. Who knows you might even save some money after 10 more years of running it like that. You know the you will still have the car then.

Go for it!

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I agree, go to EFI

 

Dont get me wrong , I love my carbies but if you are having probs and there is no one to tune them correct its not worth the hassle.

 

Ash

 

 

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What I love about my EFI setup is the drivabilty and the "set and forget" nature. Once setup, it only needs basic maintenance to keep it running well. Only downside is any major changes done to engine, exhaust etc. needs a dyno tune. Been runing an ITB setup now for over 10 years with no problems at all. With the distributor, if you want to run with a 280ZX turbo dizzy to run the coilpacks, may make it a tad cheaper. Not sure what Peter thinks about that but may be worthwhile installing one to save making a crank angle sensor setup.

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Dazzed is properly right, there is some thing we are over looking and have been chasing for a while now. As I said in the intro I recon the cam could be playing havoc with the overlap scavenging fuel back through the exhaust at lower Reeves or for some re son the extractors are not the right combo for this setup. that's the thing, there is know easy answer. You try something and it doesn't work so you just keep trying. Cam timing ,heaps of jet combos, differant dizzys, fuel pressure ,fuel volume, valve springs, crankcase pressure ,coil, ram tube length long and short and they do make a huge difference, but don't fix the tune problem. So after all this you start to wonder if the efi will sort it out.

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hay gordo let me have the car for a week will run it up in my spear time and i will fix it for you .i think you have been way to Rich on the tune for a long time ,the last time i followed you at sandown it blow black smoke the hole way around the track .dose it foul all plugs or just some..? i think the carbs will be ok when they are sorted.

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pfffft

I had my ol 2nd hand 40mm webbers setup properly from day 1 with a conservative recipe to match my stockish engine, and theve been running perfectly.

If your running a stock to mild L28 I wouldnt recommend 45mm dcoe. It sounds like your your trying to de-tune the carbs by trying to use smaller venturis...

You can only choke-back a carb so much.

what recipe is currently in them ? how worked is your engine ?

also have you considered a type 5 hotter plug ?

edit

haha Peter you posted 13 secs before me, Im sure youll sort them  ;D

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Peter. some times there will be two plugs sooted up black, not oily, and some times 3 or 4 plugs. If you put new plugs in it with a warm motor and drive it hard rev it to about 6500rpm under load and switch engine off to do a plug check they are ok in color, but then cruze around at 3000rpm and they start to foul up. I will PM you about your offer. Regards Gordon.

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PS . I am useing the type 5 plugs at the moment as the 7s  that I was useing just foul up to much. I changed the chokes from 42mm to 38mm and we found no differance, go figger. I am getting reversion at about 4000rpm but you only see it with the socks off on the dyno. That is when we played with the ram tubes. it made a heap of differance but would not fix the up and downs in the tune.

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yer the 4000rpm dip  ::) it is very hard to fix with carbs , the cam and exhust cause this if you retard the cam timing it gets better but it moves the power up the rev range about 1000rpm not so good . i have found with the injection i can tune around it ,the revershon is very bad with wade cams dial in figure but it does make the power nice and early , you will need to take up to 40% of the fuel out at 4000 to clean it up it will also be a lot nicer to drive .also i have modified the exhust which helps

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you could look at the delco efi setup, can be with our without distributor, would come in far cheaper than the price list mentioned before. also, if you get a delcohacking.net computer system, you can tune with efi-live software, which is free and everyone is using it on a lot of cars like gen3 v8s, so finding an operator shouldnt be hard. i posted some info on this a few months back, plus a L20A turbo worklog from someone else here in aus.

 

i also spotted a sexy ITB setup on a L20B the other day, apparently made by Mark Banyard (i have no idea who he is). http://www.aussiev8.com.au/holden-v8s/40389-just-sak.html#post414627

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Mark is a datsun head man in the ACT he does lots of L20b stuff and he also makes a manifold that suits the 4s ,he does not make one for 6 unfortunately .as for the delco setup i would not like to use it on a itb with no vac signal with mad reversion from a monster cam .not so nice on a race car

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Yes Peter, It's agood Idea to go with a tried and tested set up. And not trying to sort all the problems out along the way with untried setups. Cheers.

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Salty, there is one thing I love about this club, and that is the members. Where else can you post your thoughts and talk about that one common bond the old Datsun. I must admit for me a family man and a very busy life I do look forward to logging on to find out what everyone is up to. Anyway I appreciate your thoughts. As I have said the tune at the top end is good and the idle is not to bad but that middle bit is a pain in the ass.  The last dyno I had (last week) was with a differant dizzy, no air leaks on the induction side of things. So next we are going to try changing the Aux Venturi as I have heard this changes were the middle part comes in . If we can get it to come in later then we can tune it out with the mains hopefully. And after looking into the EFI, keeping in mind your not ment to skimp on things that matter which is everthing. you wont get much change out of 8--10 k. Throttle body's 3 k  helteck 2k  then there is all the other stuff associated fuel tank pumps,dizzy, coil packs, lots of bits and Pisces and a nother day on the dyno , that's an easy 8k. how can you justify that. the only way you can justify it is if you have it sitting in the bank, and I have looked and its not there. There is more to life that puntting the old datto around the track. Cheers.

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Gordon, my setup was around the $5K mark, and the only thing I had that I can use was the Redline manifold. That was with a new ECU, throttle bodies, injectors etc. Do you want to spend ages on the dyno tuning carbs or racing / driving the zed? It may seem a  bit of cash up front, but then you will save time and money later on. A good computer can be found second hand but things like pumps and injectors etc are better bought new. Give Steve Newing a call and find out some info; he can put components together for you with a budget.

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I hear you gordo part are so expensive and the faster you go the more expensive it gets , i hope you can get the carbs fixed as i love chasing your zed around the track

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Can you give us all the set-up info??

Main Jet size, Emulsion Tube Numbers, Air Correctors, Idle Jet Size, Idle Jet Tube, Choke Size, etc

 

If as Peter Mc says your car was running around Sandown and blowing black smoke the whole way, I suggest either the main jets (and maybe the idle jets as well) are too big OR the fuel bowls are too full and causing extra fuel to pass through the main jets.  What fuel pressure are you running into the carbies?

 

Unfortunately it could be so many things, but if you haven't already I'd start by checking;

  • Float levels
  • Replace the needle and seats for the fuel input to the bowls
  • Check the Idle Adjustment screws
  • Smaller Main Jets
  • Smaller Idle Jets
  • Check for wear (lateral movement) in the main throttle shaft

 

Have a read of this.  Unfortunately it's based around 4 cylinders but the principles are the same. http://www.classicrallyclub.com.au/docs/Tips_tuning_Weber_carburettors_DVAndrews.pdf

 

 

Having said all that, if you are seriously considering EFI and are prepared to spend some cash ($4k-6k) just do it.  There is absolutely no comparison between carbies & a dizzy, and fully programmable ignition and fuel management.

 

 

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Can I get some further advice on EFI on an L engine?

 

Just wondering what are the options and associated costs for timing sensors?

 

Peter Mac, does the dizzy you mention provide a timing output to the ECU?

 

Can I buy a crank angle sensor for an L?

 

Is hall effect just a coil of wire wrapped around the coil lead?

 

Zedback, I know you converted a 280zx dizzy to provide a timing output. What was involved?

 

Any other options?

 

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