Related to the Bowling & Grippo Fuel Injection system.
Post Reply
User avatar
P.Webb
Gold
Gold
Posts: 182
Joined: Mon Nov 29, 2004 9:59 am
Location: Chicago, IL
Contact:

Sensors and Injectors

Post by P.Webb »

Topic for issues relating to sensors and injectors for MegaSquirt installations. This includes but is not limited to stock Bosch sensors on Alfas.
User avatar
P.Webb
Gold
Gold
Posts: 182
Joined: Mon Nov 29, 2004 9:59 am
Location: Chicago, IL
Contact:

Post by P.Webb »

By Simon Holywell on Sunday, September 12, 2004 - 01:44 am:

Just wondering what you did as far as fuel delivery goes. I have built my ECU and started tuning. However from my calculations I think the 3.0 needs an injector supplying atleast 210cc/M as standard at 43.5psi rather than the 187cc/M currently supplied by the standard injectors.

So how did you get more fuel. Did you replace the injectors or ramp up the fuel pressure?

My car is going to be totally stock except for the removal of the AFM and swapping the airbox for a free flowing filter setup.

I am not exactly sure what to do as I am on a very limited budget now as I have had a few other un-related things go wrong with the car. I could ramp the fuel pressure up for about $200AUD but injectors look pretty expensive. I have seen Graham Gordon's site (http://www.oldebottles.com) and they are about $600AUD for the set. I would prefer a solution available in Australia as well. To save on postage and taxes.

I have the flyboard in place so I gues low impedance injectors would be the go.

Also I would think the injectors I have could do with a service or atleast tested to see what they are doing. I don't want to run lean!

I have created a new thread because the last is becoming difficult to use and find the info you need.

Thanks,
Simon

By Anonymous on Sunday, September 12, 2004 - 08:38 pm:


u add more MS of fuel... that is the whole point of aftermarket.

By Simon Holywell on Sunday, September 12, 2004 - 10:34 pm:


Well that was about as helpful as the bird that just shat on my car. Thanks Anonymous! :D

By joey on Sunday, September 12, 2004 - 10:53 pm:


yes but the stock injectors cant supply it.

simon, i think you know the answer mate.. bite the bullet.. your injectors are old and parts binned with the 2.5 anyway, although i'm not sure but a stockie 3.0 should be alright with stock injectors... with more duration..

if u want to keep the duty cycle at .8, then yeah your calculations would be right. (for an engine producing about 190hp), an injector flowing 187 is only good for 171hp, so i'm guessing the stock computer for the 3.0 is running more than 80% duty cycle? do you know where its at now?

i would stuff the low impendance old type and go with new motronic injectors, should be a few good performance shops near you where u can source new or used. obviously u know that the MS can run these fine w/o the flyback board.

but IMO if it comes to shipping from the US (from greg), 600 aud sounds good for new injectors, vs wasting $200 in upping pressure on ~15yo injectors.. JMO anyway.

ps: if you are getting them from greg instead of sourcing them from OZ, then i guess you're right with the l-jet type, its about 100US cheaper and i s'pose that means u can go back to stock computer if need be..

good luck and let us know..

By joey on Sunday, September 12, 2004 - 11:04 pm:


lol, didnt see that response by simon..
those airborne bastards are a real bane of immaculate paint finishes !! grrr

stocker 3.0 ecu must be around 85% duty me thinks...

i'm sure you're not a melbourne alfisti, so i dunno any good shops.. but your local ricer tuning joint should have a big selection of motronic type, probably used and on the cheap since no one running turbo 4s would want <300cc/min injectors..

might like to try benincas for advice, he's always helpful and can give good info on the 3.0 alfas in particular...

http://www.beninca.com.au/

By Simon Holywell on Monday, September 13, 2004 - 06:04 am:


I am in Melbourne out near Narre Warren, so not many decent places for this kind of thing round here. I just had a few things done by Beninca and thats why I am so poor!

I have not got any idea of what the stock ecu is running the stock injectors at unfortunately.

Also why get rid of the low impedance injectors? I would prefer to be able to stick the stock ecu back on when I sell it you see.

Thanks for your reply,
Simon

By Peter Webb on Monday, September 13, 2004 - 09:33 am:


Sounds like all calculations are correct. You can run 85% duty cycle which is dead on for the stock HP rating of the 3.0. But you don't explain how you arrived at the 210cm3 number. Power is about air, not fuel. Volumetric efficiency is how you make power. Remember the diatribe about BSFC and the potential energy of fuel minus mechanical loss?

If you're running low-z injectors, running them over 85% DC can stick them or fry them. Even with the flyback board. The problem is getting high-z injetors in barb style. You can't use the o-ring (Motronic) style with the stock fuel rail, nor can you use the 164 style rail because of the twists and turns in it to clear the runners. A suggestion would be to make a rail using Aeroquip flexible line on barbs. That can get pretty expensive.

The point of aftermarket control is to change the amount of fuel at specific points in volumetric efficiency up to the capacity of the injectors. You can't get an injector to physically flow more than it's capable of even if commanded to do so. This must be the same anonymous nitwit that challenged me over on the other thread with the same ignorant rhetoric. Obviously doesn't understand the first thing about engine managment.

I'd like to see a datalog from your car to support this theory. Make sure you select "full". You can email it to me at the above address.

-Peter

By Jaques on Monday, September 13, 2004 - 10:25 am:


Hi Peter. Yeah I know this is another stupid question but maybe you can tell me where im going wrong. My 2.5 GTV has a(stock - no mods)) 3.0l motor in it with the stndard L-Jet that came with the GTV. The injectors and airflow meter were all from the 2.5. This car produced good power to run alongside my 75 3.0l however the problem is that my fuel consumption was pretty shocking. I then used a BMW airflow meter which is larger with the 2.5 circuit board in to give me greater airflow and to reduce the spring tesion like I had in the 2.5AFM. My problem is that either I have way to much fuel flying out the exhaust to make the car perform properly or good co's at idle and no power. By chainging to larger injectors(3.0L)will this solve my problem as maybe I acn lean out the system and get better co's across the rainge or is that total crap. What do you think is the best solution to give reasonable power and consumption using the the stadard ECU. Im not after big power as i have my race bikes for that. thanks

By Greg Gordon on Monday, September 13, 2004 - 11:17 am:


Peter, I think diatribe is an overly harsh term. I thought of it as a freindly discussion.

By Peter Webb on Monday, September 13, 2004 - 12:11 pm:


Yeah, sorry about that. Didn't mean to imply any bad feelings.

-Peter

By Greg Gordon on Monday, September 13, 2004 - 02:45 pm:


No Problem, I am thinking about building a Megasquirt system for my car.

By Simon Holywell on Monday, September 13, 2004 - 05:55 pm:


To get 210cm3 I averaged all the horse power figures I could find for the 3.0l 75 engine (manual and websites close to the manual). This gave me about 183bhp which I calculated with a BSFC of 0.50. And maintained the duty cycle at 80%. I used the following calculator: http://www.injector.com/injectorselection.php Which I think was posted on another threaded on here that I found whilst searching. Upon calculating again I discovered that I must have copied the number over to here incorrectly as I am now getting 200.16cc/M

Please stop hijacking the thread. This is the MegaSquirt section of the board here, so perhaps standard ECU questions would be better asked in the standard section of the board?

And who's diatribe? I cannot see any mention of diatribe in this thread.

By joey on Monday, September 13, 2004 - 06:13 pm:


so, the stock 3.0 computer does run the injectors at 85%?

if my assumptions are ok, the 210 figure is arrived at the guesstimation of 190hp, using the same constants that arrived at 187cc/m @ 85% duty = 183hp stock ratings for the 3.0... reducing the duty to .8 and expecing around 190 peak, resulted in the 'need' for 210cc/m injectors... but thats why i suggested benincas, he would instinctively know what to use and what works best for these modernised motors...

i thought greg's motronic type injectors are a direct fit replacement? sticks right onto the stock fuel rail?

IIRC peter, your engine is quite warmed over isn't it? what injectors are you running?

cheers

By joey on Monday, September 13, 2004 - 06:18 pm:


damnit simon, you're always doing that !!

simon, go to your explorer menus, edit > Find (on this page)... it a great tool !!

By Peter Webb on Monday, September 13, 2004 - 09:40 pm:


Yes, my motor is a little "warmed over". I'm using 24lb 350SBC injectors @ 65psi rail pressure bringing them to ~28lb. I'm running about 300hp with the triple throttle setup.

Lets dispell the notion that there's a "Motronic" injector. There are o-ring type and barb type, there are high-z and low-z.

L-jet uses low-z injectors, Motronic uses high-z injectors. There are pluses and minuses to both. The MegaSquirt can work with both if the low-z injectors are the 2.4ohm type, or with a flyback board if they are the 1.3ohm type, typically on TBI and rotary setups. There is a specific reason for this which we won't cover here since this is an Alfa board, but you can research it on the www.msefi.com forum under the tuning threads.

So that said, you have a choice of impedance with injectors but you have to deal with physical fit and characteristics. The GTV6 and Milano/75 use barb type injectors due to the fuel rail design. That's not to say a custom rail can't be made to take o-ring type injectors.

Barb type injectors are getting harder and harder to find. Not many marques used them originally and none do now. Several cars used the o-ring style injector, and while they are called a Bosch style injector, they are made by Denso, Siemens, Accel, Motorcraft and Delco.

Matching flow is the most important thing. You won't get idle resolution by oversizing but it is possible to play with opening times to get good resolution for large injectors. Hence their use on TBI systems.

Getting the flow close and setting the REQ_FUEL is the most important thing. The the VE table can be adjusted to get the correct AFR. Finally, enrichments and corrections are applied.

You should use a reasonable sized high-z injector if you can. Only because there's a lot less to do to get it to work and tune. Something in the 210cm/3 range should be fine, but not required. Remember, an engine is an airpump. The better the VE, the more fuel you need. This is achieved by ports, cams, valves etc. Getting more air in and out of the motor and scaling the fuel accordingly.

Unless you've made significant changes to move more air in and out of the motor, more fuel is not going to help. Removing the AFM helps in that regard and I was able to get another 24hp doing that. But I have ported and shaved heads and some radical cams. Remember, it's an air pump. It's only as good as it's smallest restriction. I know that's over simplifying things as far as air characteristics like velocity but the general model holds true.

BSFC is .45 for naturally aspirated engines, .55 for forced induction. That's a pretty accepted standard. Simply because it requires energy to turn the impeller. Following the air pump model, forced induction sends the VE over 100% by pressurizing the intake and cylinders which in turn requires more fuel. Otherwise you run lean and melt things.

From the discussion previously, BSFC is basically the ratio of the potential energy of fuel (gasoline) converted to output energy. Naturally aspirated engines are able to convert 55% of the potential energy to output, where forced induction can only convert 45%, with 10% of the fuels energy being used to turn the impeller.

So what does that all mean? It means that the Alfa 3.0 is capable of 189hp at 100% VE given the stock components, and .45 of that is used to turn the engine, so injectors are sized to run a 14.7:1 AFR with the potential energy to produce 274hp - 45% loss. Increasing the airflow increases the volumetric efficiency increases the AFR which needs more fuel to increase the output of the engine.

Make sense?

-Peter

P.S. Simon, send me that datalog. I'd like to see what you're experiencing.

By Simon Holywell on Monday, September 13, 2004 - 10:59 pm:


Peter,

So what I think your saying is that the standard components are only good for 162.85hp? (274hp*0.45)

Thank you for your informative reply, but I must admit it is about now that I get in over my head. Building the MS and tuning it makes far more sense to me than fuel pressure and injector sizing does. I think I need to talk to a family member who has more mechanical experience. Unfortunately however I think that EFI is going to be over their head as they owned carbied cars and motorbikes before the company car.

I do not have a full datalog from the car because I have not been able to drive it on the MS yet. The day after I finished the MS and fitted it my sister needed her laptop back for the school term. So I have been running on L-Jet ever since.

The only datalog I have is from the car idling in the garage and being revved a little bit to test the tach circuit modifications. I had the desktop PC in the garage. I have a Palm based device that I plan to use soon, but I don't really have time right now due to uni. I am also waiting on an adapter plate to fit the Spectrol TPS I have to the original throttle body. The local Alfa car breakers wanted $200AUD for a 164 throttle!

Thanks,
Simon

By joey on Tuesday, September 14, 2004 - 01:05 am:


yes thats true, the point is greg advertises high-z injectors that fit our rail !

"motronic style" being that they will work an any motronic based ecu, whereas as you know, those a/m systems or even OEM motronic-type ecus would melt at the thought of low-z injectors...

and your point is exactly correct, no one uses the oem barb style of these cars anymore, which is why i suspect that the chances of finding these "motronic style" (okay.. high-z) new or second hand that will work are greater...here in australia especially.

still after all is said and done, you would probably be a lot better off and save yourself some headache if you just pick up some of greg's
"low-z oem replacement barb style" injectors... i just looked and they're around 500AUD + shipping, which for these lil' buggers probably wont be much.. i got the whole MS kit plus components shipped for 12USD.. no biggie

500 bucks for brand spanking new more capable injectors vs 200 for upping pressure on 15yo injectors already on the limit is a simple choice IMO.

but being a fellow student i fully understand your cash concerns !! prolly should have thought of that before you bought an alfa ! heh (okay, not funny ...)

ps: why changing the TPS? steve found a way of changing teh MS to accept the different "grades" of TP with the stock unit.. are you not happy with this or prefer the tuning to be done )or corrected) by TPS?

as far as i'm concerned i dont think i could care less, i'll let the MAP do its thing.

By joey on Tuesday, September 14, 2004 - 01:35 am:


so what is the general opinion here?

i understand what you are saying re: breathing - as i said myself before, stock injectors should be okay for a stock engine...

BUT, can we assume that the stock 3.0l injectors are too small for the job in the first place? i think i read somewhere that injectors are ideal around 80% DC, and pretty useable up to @ 90%. but usually for the saftey of the injectors values of 80-85 are usually desired.

would the removal of the AFM push the limits of the stock injectors over the border of acceptable use? i figure i would expect to see >5hp and <10hp on a stock 2.5, i dunno about a 3.0... As i understand it copped bigger valves but a lazy cam.. still with its greater displacement and a little more compression, i would think 10hp-15hp range.

if the stock power is given at 183hp, then even at 90%DC, the most the injectors can supply is around 193hp.. which may not be sufficient for a totally stock but AFM-less 3.0 motor.

sooo, can the stock injectors be made to work reliably on the AFM-less MS?

greg, your site says that the stage 2 l-jet replacement injectors are good for up to 250hp, but what do they flow specifically? what would be their DC @190hp? what DC / pressure was used to come up with 250?

the stock l-jet injectors i think max out at 200hp according to gregs site, but that must be at a DC of 94% @ 43.5psi !!

cheers as always

By Zamani on Tuesday, September 14, 2004 - 02:54 am:


Joey,

Habibi, my injectors run >90%. Not that I can help it, cash is lacking right now. These are stock, balanced and cleaned injectors. I'm going with something similar to Mats'. Bosch Gen3. with 164 intakes (just bought it last month)

By Simon Holywell on Tuesday, September 14, 2004 - 05:48 am:


Yeah I will be using the TPSdot acceleration enrichments. This is because under intial testing the MAPdot code seemed quite slow to respond to the acclerator. I want it to respond immediately especially as the car can find itself on the track once in a while.

I was looking at the stage2 injectors Greg has on his site when I got the ~$600AUD figure. Without knowing the exact flows though it is difficult to figure out which would be better. But I guess in my case the OEM replacement units are the best option. Although I am not sure. Think I might run off Beninca and Greg an email asking what they can do and suggest.

Oh yeah and when I was getting the suspension and exhaust (ouch!!) replaced/adjusted by Beninca I asked how much it would cost for them to tune the MS. They wanted $800 even after I had tuned the cold start, which would be I would think the most time consuming part of the whole process!

Simon

By Greg Gordon on Tuesday, September 14, 2004 - 07:22 am:


Wow, a lot to comment on here.
First of all Joey...I do have high resistance injectors that fit our fuel rail and injector ports. Thanks for pointing that out. They have a barbed fitting. I call those Motronic type although as Peter pointed out that is not technically correct since some Motronic cars use injectors with different configurations. Perhaps I will start calling them high resistance barbed type injectors that will fit our cars.

I will put exact flow rates and pressures on my site. I should have done that long ago but never bothered. I don't want to post them here because I can't edit my posts to reflect changes in my product line. In other words if I say injector "A" flows 25pph and I change my product line and have a new injector "A" that flows 28pph it could cause confusion. Therefore I try to limit my posting of product specs to my site.

On my site I suggest stock sized injectors for 180-200 hp engines. The 200 hp is an absolute upper limit and depending on which formula you use shows a duration of around 90%. That's too high for me but some people do get away with it. I do think our engines have a higher BSFC then we give it credit for because there are people running even more power on the stock injectors.


Speaking of BSFC, removal of the AFM improves it so not all of the resulting power gains require extra fuel. In other words if removing the AFM gives a 10 hp gain some of that gain, perhaps 5 hp (I don't have real numbers on this) comes from improving the BSFC in which case you would only need extra fuel for 5 hp. Intake and exhast improvements work this way so it's reasonable that 200 hp could be had with stock injectors although I don't recommend it.

Peter, I think we are now on the same page regarding BSFC. No big deal, in practical terms it's just a number we plug into a formula and we are both using the same numbers .45 and .55.

By joey on Tuesday, September 14, 2004 - 07:29 am:


z, we know it can be done, but its hardly ideal to buy brand new stock injectors and run them at damn near 100%DC.. thats a good way to give em a short life.

thing is right now, its unclear if the stage 2 stuff offered by greg is ideal for a stockie 3.0.

simon, did not know that.. although that makes sense - i'll have to see for myself.. looks like i'll have to start looking for a TS TPS now though.. hrmm

By Dennis de Rooy on Tuesday, September 14, 2004 - 01:12 pm:


Hey Joey, what kind of TS TPS do you need? I can't find it exactly in this thread, but since there are a lot of Alfa's parted out over here in the Netherlands, maybe I can help out.

By joey on Tuesday, September 14, 2004 - 11:17 pm:


thanks denis, thats a very kind offer.

i think i heard that the milano/75 TS throttle body is a good one to use.. but i dont know if it physically fits the gtv6. i would like to see tho..

as per peter's other thread the TPS you want is "TPS 0 280 122 001. It's commonly used on the 164QV, 155, Volvo 850, BMW E46"

however, some seem to have great results with running straight off the MAP, and dont need the assistence of the TPS, others find it necessary. seems a bit hit and miss which is understandable given the different engine setups everyone has in conjunction with this DIY kit.

so as i said, i'll like to see if i can get away with MAP only, i'ld like to avoid the extra un-necesasry expense and headache if possible..

cheers for the offer though, i may take you up on that if need be.. here's hoping i wont !

By Greg Gordon on Wednesday, September 29, 2004 - 01:27 pm:


OK, as promised I have put flow rate information for all of my injectors on page 5 of my web site. www.oldebottles.com
User avatar
Michael
Site Admin
Site Admin
Posts: 515
Joined: Sun Nov 21, 2004 12:00 pm
Location: Seattle, WA, USA
Contact:

Post by Michael »

Hey Guys:

Just curious - if I was to install one of Greg's supercharger kits (mine is a 3 liter), he reckons that I should use 'stage 2' injectors which flow a bit more fuel.
Now, if I have to buy new injectors anyway, which would be the best as regards Megasquirt? Can I get high impedance injectors for my GTV6? I currently have the flyback board installed and using this with my stock injectors.

Cheers,
Michael
1981 GTV6
User avatar
Steve R
Platinum
Platinum
Posts: 237
Joined: Wed Nov 24, 2004 1:06 pm
Location: Dorset UK

Post by Steve R »

I thought about increasing the pressure but decided against it, now I've ordered a set of Greg's high Z larger injectors, should do the trick and be a once and for all solution.

Increasing the fuel pressure would have been cheaper, but I'd worry it would be more prone to failure on 22+ year old bosch injector and pump hardware.
83' GTV6, 3.0 24v supercharged
User avatar
Michael
Site Admin
Site Admin
Posts: 515
Joined: Sun Nov 21, 2004 12:00 pm
Location: Seattle, WA, USA
Contact:

Post by Michael »

Thanks Steve.
By the way, I can still use the (anti) flyback board even with high impedance injectors I presume?
Michael
1981 GTV6
Post Reply