Switching to efi and need guidance

[racer189]

Application:
- Endurance marine racing.
- Goals trying to achieve - more consistent and controlled fuel control in extreme conditions in order to prolong engine life, Can't win if we don't finish - average engine attrition rate is about 25% between all classes in a single weekend event and 50%+ attrition over a Marathon event 500+ miles with 5 hrs @ WOT.
- Up to 45 minutes at WOT @ 6000 rpm per leg.
- up to 2000 ft Density altitude changes between morning and afternoon races, up to 4500 ft density altitude changes between race/event locations
- Would like closed loop tuning with at least 2 - O2 sensors, prefer having the ability for 8 for initial tuning and then will run 1 in each bank closed loop under race conditions.
- User friendly tuning for someone that has never done this like me.
- MPI -Individual cylinder fuel and timing adjustment for initial tuning?
- All in one ECU for both fuel and ignition management
- ability for ECU to read OEM knock sensors and adjust timing as necessary under closed loop

Current engine
- LSX 454
- 720 hp @ 6000 rpm and currently uses about 38 US gph @ WOT @ 6000 rpm
- Holley Hi ram with twin Willys 750 4150 carbs
- running C12 or Fury 108
- OEM Coil on plug ignition with 58X crank sensor
- OEM cam sensor

Need recommendations for
- ecu's - Currently looking at:
- Holley Dominator - appears to be able to sample 2 O2 sensors in closed loop but would like to use 8 for initial tuning and then 2 for closed loop under race conditions (this does not appear to be available with the Holley), self learning, appears to have built in ignition control, allows individual cylinder tuning.
- Have looked at FAST but needs a separate ignition box, but appears to have the ability to monitor 8 O2 sensors
- Motec - has everything but very expensive
- Haltech - new Elite series appears to have most everything but not available yet

- injector sizing, brands, styles? Is it necessary to oversize the injectors inorder to have a sufficient duty cycle for extended periods (up to 45 minutes)at WOT?

- throttle body size, style? - Single bore, 4150 or 4500 style 4 bbl, Single or twin 4 bbl MPI and what size? Wider bore spacing on a 4500 series gives a better line of sight with my tunnel ram ports but not sure if this matters in a MPI set up?
- Do spacers help on a MPI set up like they do on a carb?

As referenced above, I'm an EFI virgin ......at least in a race application, so I welcome all comments and suggestions so I can learn as much as possible. I've talked to many different efi suppliers and have received conflicting and contradicting advice. I tried to supply as much info as possible inorder for you to make educated comments, however please don't hesitate to ask for something I may have missed or suggest something I that I should take into account for this application.

Thanks in advance!

[RL]

Application:
- Endurance marine racing.
- Goals trying to achieve - more consistent and controlled fuel control in extreme conditions in order to prolong engine life, Can't win if we don't finish - average engine attrition rate is about 25% between all classes in a single weekend event and 50%+ attrition over a Marathon event 500+ miles with 5 hrs @ WOT.

Wow, that's high. NASCAR engines run 9250 rpm for 2 hrs, so it's probably not the engine - maybe the prop free wheeling kills them -.

This country has an abnormally high number of ECU builders.
Motec is regarded as #1
Autronic was regarded equal a couple of decades ago but wouldn't have a clues these days because no one mentions them any more.
Haltech is the next best option
Microtech, EMS, Wolf, were regarded all about equal.

There is probably no difference between them - I wouldn't be surprised if they all use the same chip just with different conditioning -, so the choice is more emotional rather then factual.

[xenginebuilder]

I can only pass on my experience with a similar racing requirement, for me it was endurance racing on road courses of 6 -12- 24 hour races. The team I was building engines for initially used EFI Technology for ECU, but later switched to Motec. We were happier overall with the Motec, and from a reliability standpoint never had an issue with the Motec components. I can't say to how they would do in a marine environment, but from a heat and vibration standpoint they did fine. We were first using 4 dual seconday coils, then switched to coil on plug. One of the first "retrofit" projects we did was to convert a desert race "Trohpy Truck" from carbureted to EFI, and while the cost of conversion was pretty expensive when you include diffferet manifolding, air cleaner, fuel system, pumps, sensors, etc., the end result was about a 30 to 50% increase in fuel mileage just because the fuel injections was immune to all the shocks and bumps. It also makes rev limiting a better alternative to a carbureted setup where you are locked in to an ignition based limit, with the EFI you can shut off the fuel at the injector which is a lot easier on parts and does not produce the bangity bang you get with ignition limiters. It seem like with the marine stuff you spend half the time out of the water, so engine rev control seems to me to be a pretty big factor.
As far as cost, I think if you work up some true costs for all the features and flexibility for future upgrades you might want, the Motec might not look so bad.
As far as ease of use, you NEED a EFI guru/geek to set you up and get everything sorted. Adjustments at the event are pretty easy, but I would not recommend a beginner trying to get a new combinaiton up and running without some help.

[ijames]

Here is a link to a post by one of the resident efi experts, dieselgeek, on how he did what you want for the 2012 EMC competition: viewtopic.php?f=15&t=29960&p=354885&hil ... ng#p354885. Maybe give him a shout if he doesn't see this thread?

[HaxbySpeed]

You can monitor and datalog 8 individual O2's with the Dominator, but it will only self tune off 2. You really only need one though for the type of racing you do. The Holley has a ton of features and flexibility for the $, huge dataloging capability, and is incredibly user friendly. It's also a very durable unit, epoxy encapsulated, and a direct plug and play for the LSX. You could save a couple bucks by converting your existing intake.

[racer189]

You can monitor and datalog 8 individual O2's with the Dominator, but it will only self tune off 2. You really only need one though for the type of racing you do. The Holley has a ton of features and flexibility for the $, huge dataloging capability, and is incredibly user friendly. It's also a very durable unit, epoxy encapsulated, and a direct plug and play for the LSX. You could save a couple bucks by converting your existing intake.

I didn't realize I can monitor 8- O2's, on the Holley

I'm curious about throttle body size and style. Is a person better of using 2 separate throttle bodies (2x1000 cfm) for better line of sight for carb/tunnel ram intake ports, or save money and complexity by just using 1- 2000 cfm large unit?

Is throttle body port design important? The port design on the Fast/Accufab tb's are quite different compared to Holleys/Wilson, Edelbrocks?

Thanks again.

[racer189]

What about injectors for this endurance application:
- low or high Z?
- is it better to oversize the injector because it is an endurance sustained WOT application and is their a downside to going too big?
- Spray patterns?
- Manufacturer recommendations? Holley, AFIS, Venom, ID, Siemans, etc

Any other advice is appreciated.

[The Radius Kid]

What about injectors for this endurance application:
- low or high Z?
- is it better to oversize the injector because it is an endurance sustained WOT application and is their a downside to going too big?
- Spray patterns?
- Manufacturer recommendations? Holley, AFIS, Venom, ID, Siemans, etc

Any other advice is appreciated.

I'd go low Z and size the injector with about 20% left on the table.
Bosch makes a nice injector.
Spray pattern will depend on the angle of the spray to the port air flow.

[jacksoni]

What about injectors for this endurance application:
- low or high Z?
- is it better to oversize the injector because it is an endurance sustained WOT application and is their a downside to going too big?
- Spray patterns?
- Manufacturer recommendations? Holley, AFIS, Venom, ID, Siemans, etc

Any other advice is appreciated.

Low or hi impedance a function of the ECU and what it will drive. Some will drive both, some only one or the other. My sense is more high flow injectors are hi impedance these days but as you are NA you won't need giant ones. Easy formulas to calculate the size. To avoid having the injector always open and therefore going out of tune (or getting hot), generally recommended to have an 80-85% max duty cycle. Again easy online calculators. Some ECU may have trouble idle tuning an injector that it "too big" and there is no real advantage to "too big" (unless you change the engine and have to buy new for more power). Injector doesn't know and doesn't care that you are WOT for an hour or two or whatever. Same as your car cruising down the highway at 70mph hours on end. Just as long as you don't go to 100% duty cycle. I use Siemans which is Bosch like EV1 type and they have worked very well. There are lots of others and specialty mfgs as well. I think many are just relabeled.

[The Radius Kid]

What about injectors for this endurance application:
- low or high Z?
- is it better to oversize the injector because it is an endurance sustained WOT application and is their a downside to going too big?
- Spray patterns?
- Manufacturer recommendations? Holley, AFIS, Venom, ID, Siemans, etc

Any other advice is appreciated.

Low or hi impedance a function of the ECU and what it will drive. Some will drive both, some only one or the other. My sense is more high flow injectors are hi impedance these days but as you are NA you won't need giant ones. Easy formulas to calculate the size. To avoid having the injector always open and therefore going out of tune (or getting hot), generally recommended to have an 80-85% max duty cycle. Again easy online calculators. Some ECU may have trouble idle tuning an injector that it "too big" and there is no real advantage to "too big" (unless you change the engine and have to buy new for more power). Injector doesn't know and doesn't care that you are WOT for an hour or two or whatever. Same as your car cruising down the highway at 70mph hours on end. Just as long as you don't go to 100% duty cycle. I use Siemans which is Bosch like EV1 type and they have worked very well. There are lots of others and specialty mfgs as well. I think many are just relabeled.

Good points.
The ECU could be as easy as an lS1 and harness out of a Camaro.
You've got cylinder skewing built in and a few laptop based programs that can tune it such as HP Tuners,etc.

http://www.witchhunter.com/injectorcalc1.php


One more thing I should mention is the old rule of thumb:

When the size of your injector in CC's exceeds the displacement of the cylinder it's feeding in CC's,you may have idle issues.
Newer injector designs may help alleviate this to a point,but not totally relieve it.

[racer189]

I think I'm going to go with the Holley Dominator ECU, it does most everything I want and more, plus will integrate with my Racepak. The Dominator will drive either low or high Z, so I can use whichever will work best for my application.

Using the injector calculator from the above link, I get 62.5 lb or 656 cc size recommendation using 800 hp, which I hope the engine will be after some improvements to be made to it, it might be as low as 750 but I would like some wiggle room. My cam will be a hydraulic roller with about .700 lift, am I going to have idle issues with this big of injectors? Take note we only operate at or below 1500 rpm for the 30-60 seconds when loading the boat on the trailer, everything else is above that.

What about spray patterns, V, pencil, 4 hole, 10 hole, etc?

I see injectors in this size range priced from $350 - $1500 set, is it worth the extra money? There are so many manufacturers like Holley, Edelbrock, Fast, Deatsch, Bosch, Siemans, Accel, FIC, ID, etc, that its very hard for a greenhorn to tell the difference between good, better and best when they all look the same and they each say they are the best high performance injectors in the industry? I would have to imagine that many are the same injectors, just relabeled and sold under different names??

What about matched sets or manufacturers that say their injectors are within 1%+/- like AFIS? I watched a youtube video showing a test on a set of brand new injectors that had significantly different volumes between them.

Thanks again.

[The Radius Kid]

I think I'm going to go with the Holley Dominator ECU, it does most everything I want and more, plus will integrate with my Racepak. The Dominator will drive either low or high Z, so I can use whichever will work best for my application.

Using the injector calculator from the above link, I get 62.5 lb or 656 cc size recommendation using 800 hp, which I hope the engine will be after some improvements to be made to it, it might be as low as 750 but I would like some wiggle room. My cam will be a hydraulic roller with about .700 lift, am I going to have idle issues with this big of injectors? Take note we only operate at or below 1500 rpm for the 30-60 seconds when loading the boat on the trailer, everything else is above that.

What about spray patterns, V, pencil, 4 hole, 10 hole, etc?

I see injectors in this size range priced from $350 - $1500 set, is it worth the extra money? There are so many manufacturers like Holley, Edelbrock, Fast, Deatsch, Bosch, Siemans, Accel, FIC, ID, etc, that its very hard for a greenhorn to tell the difference between good, better and best when they all look the same and they each say they are the best high performance injectors in the industry? I would have to imagine that many are the same injectors, just relabeled and sold under different names??

What about matched sets or manufacturers that say their injectors are within 1%+/- like AFIS? I watched a youtube video showing a test on a set of brand new injectors that had significantly different volumes between them.

Thanks again.

http://racetronix.com/products/

http://www.kinsler.com/

[HaxbySpeed]

There are lots of opinions out there.. The best thing you can do is, buy your EFI system from a reputable dealer that has tuning experience with the unit, and understands your application. This will save you time, money and frustration. I think the dual 4150's are the way to go, but it would be fun to try a big single on dyno to compare, top, or front mount. The design of the upper half of the plenum is important. Call Holley direct, and ask who they'd recommend.

[ijames]

Just a data point about idling big injectors: the stock 3.8L Buick V6 is 38.5 cubic inches per cylinder and with 83 lb/hr injectors they idle fine. I've fast passed the IM240 emissions test twice with 72 lb/hr injectors so no horrendous unburnt HC issues or anything like that. The 96's are ok but sometimes a bit rough and/or need a higher idle speed, 120's will load up the plugs sometimes, and 160's are tough. Step up to 45 cu in per hole (stroked 4.1 L) and even the 160's idle ok.