Mechanical Injection Manifold

[CTX-SLPR]

Howdy,

Now I know that I'm not asking about something using Stage Heads (illegal in the class I'm racing) but of the entire board population, the majority of the past/present users of Mechanical FI are here.

I've been talked out of using a blowthrough carb by the local speedshop/engine builder who has actually been to Bonneville and run over 200mph. My goals of ~145-150 are staggeringly short of that but still experience weighs heavily here. He showed me an Enderle version of Ron's Flying Toilet that greatly intrigued me. It really opened my eyes to MFI not being just stacks and dedicated manifolding. While that might be better it's not likely required for my goals. I'm also still trying to get my head wrapped around the fuel flow increase due to boost but I'll figure that out seperately.

I'm looking for a recommendation on what kind of manifold to run. I'll start out by saying that I have to run production type heads so I am limited to what will fit production type heads on an Off Center block. Likewise I don't have the money or the perceived need for a Champion/BGC intake. My real choices are the 86-87 with power plate and maybe an aftermarket plenum, or FWD EFI intake for forward facing dry flow intakes. The OEM 4.1 4bbl with a lot of plenum work and the EGR filled, KB #1, or a Weiand; all with some form of elbow and forward facing TB.

Main reason for forward facing throttles is that it's cheaper for a single TB with straight plumbing vs. buying a carb hat for on top of a 4150 flanged 4bbl TB. Also testing I've read from Steve Morris Racing Engines (who makes carb hats and helped design the original Extreme Velocity hats) says they see equal to slightly better performance with a good elbow to thier own hats. I have an OEM 4.1L 4bbl intake and FWD EFI intakes are cheap at a junkyard. The rest I'd have to buy and that looks like ~$200-300 for most of them. I can and probably will fab my own elbow and do port work if needed.

I need all the money I can save on pretty much everything so I can fit more of what I need into the budget I carved out of my tax return. I'm not planning on going stupid cheap but at a 300-350hp target (I'll get what I get with my combo of parts but I plan on making 300-350hp at the flywheel) I can afford to use some low grade parts intially. I'll step up the parts as my buget allows me things like a Stage block and a forged/billet crank that I can massage into a <183cid combo.

Thanks,

 

[Mike E]

I would try to use an 86-87 stock intake/plenum and throttlebody. People have made over 1k hp with them. The price is right and they are easier to source than a weiand. Spend your money on the fuel system. Turbo and mfi has it's own unique set of challenges. A call to my friend Travis Quillen would be wise. http://www.quillenmotorsports.com/ He will give you the straight scoop on what you need. He has done turbo mfi on turbo vw motors, ford 2.3 4cyl turbo's and up to pro mod hemi turbo stuff. He has his own flow bench and a line of his own nozzles, regulators, barrel valves, etc. And because of my motor he knows something about buick v6's.

Some of his intakes are in this thread. http://www.yellowbullet.com/forum/showthread.php?t=189466&highlight=Quillen&page=9

Don't bother with a power plate. The mfi will give good individual cylinder control to balance lean or rich cylinders.

 

[CTX-SLPR]

Mike,

Thanks for the recomendation on him, I've seen him refferenced on both turboforums.com and yellowbullet.com as the go to guy for MFI. I'll call him and Hilborn this week and see what they have to say about boost responce.

While I'm sure I could tune fuel to air on a cylinder to cylinder basis with the MFI, why would I not try to equalize the air flow itself with the powerplate? I have one on a shelf already.

 

[Mike E]

Would you block 75% of the best flowing intake port in you heads? Thats what your doing with the power plate. If your whole motor is lean, you don't block air coming in to richen it, you add more fuel. Your taking the best flowing runners and pulling them back to match the worst. That sounds counterproductive.

The reason some cylinders get more air is mostly because the air is coming in the plenum so fast it can't make the turn to the front cylinders. If you could slow down that air it would make the turn better. That is basically what a plenum spacer does. It adds volume and room to slow the air down. It also makes the turn into the front cylinders easier.

 

[CTX-SLPR]

Well I also have a plenum spacer on the shelf next to the power plate, could use that instead.

Edit: I feel my upper plenum designs are off topic so I removed them. Does anyone one else have some suggestions or input on a manifold for MFI?

Thanks,

 

[dr_frankenstein]

the mechanical injection is going to outweigh itself in cost to ease, as well as the complexity to set up. I tired a single throat hilborn unit on a draw thru motor awhile back and it was a real pain in the arse. pumps, poppets, hi speed bypasses, jet selctors, etc etc, will catch you and make you pull your hair out.

there is almost little to no midrange or cruise performance..... easiest way to see MFI is ON or OFF.... nuthing inbetween.

why the desire for the MFI? your not making nearly enough power to make the work worth it... carb is well suited to anything your doing till like 1000hp.

 

[CTX-SLPR]

It's a Bonneville car; the jungle gym of a cage, steering limiters, lack of real cooling system, and many other things will keep this thing off of the street so I'm not terribly concerned about a lack of cruise performance. I'll be running the car between 75-100% WOT for most of the run anyway, part throttle will just be for when I'm traction limited.

While I agree I'm definately in the shallow end of the pool right now, I'm not going to stay there and the carb is going to start requiring more and more modifications as I ramp up the HP. MFI "should" be able to keep the majority of the same parts other than tuning bits from my intial target up through the end goal. Another thing on the cost side is with a carb I will need to buy a carb, then modify it, then buy a hat, and support it with the fuel system. With MFI, all the cost really is in the fuel system; pump, barrel valve, boost sensor, and nozzles. Looking at prices, the pumps are near the same cost, the boost sensor and a rising rate regulator are near the same cost, and the barrell valve near the same cost of a 4150 and rebuild kit. I'm not seeing a cost advantage for the carb. Plus I can honestly wrap my head around MFI easier than I can carb. I'm willing to try and learn, worst case I beak something (likely with a carb too) and just sell all the stuff off on Racingjunk.

Any big objections to a 86-87 EFI intake or anyone see a problem with the FWD intake (other than it's backwards)?

 

[Mike E]

The FWD intake would probably work also if the ports line up correctly. You can mount the manifold backwards (tb in front) and run the water however you want. With alcohol, cooling will not be a problem at all. You might have a hard time making enough engine heat. It should also allow you to block off the front of the car 100% for aero.

 

[CTX-SLPR]

Well I'll be running gas in 3 of the 4 classes I'd be racing in. I can always put the intercooler in the passengers compartment and route the air in that way. I could also cut the top off and weld one of RJC's plenum reverser spacers or another aluminum spacer to increase the plenum volume and turn the TB around...

 

[CTX-SLPR]

Mike,

Thanks for the recomendation on him, I've seen him refferenced on both turboforums.com and yellowbullet.com as the go to guy for MFI. I'll call him and Hilborn this week and see what they have to say about boost responce.

Well Travis is a no go, he doesn't do gasoline, just methanol. Hilborn was marginally helpfull but looks a bit over complicated.

Leaning towards using Enderle primary components to tune it NA then hacking together my own boost enrichment using a modified Bosch K-jetronic fuel distributor as a linear enrichment device. Really wondering if the equation for extra fuel is Const x Boost or Const x Boost x RPM. In other words, do I need to add fuel off of the RPM dependent engine pump or a seperate constant pressure electric.

 

[Mike E]

I can see why he wouldn't want to mess with gas. It takes less than half as much gas as it does methanol to make the same power. With the pumps, nozzles and valves available it would be really hard to work with 1/2 as much fuel.

 

[Reggie West]

Call Ken Dutweiler and ask him for some advice......

 

[dr_frankenstein]

gas should be easy, as it will take less parts and smaller parts to flow the needed amount of fuel and with reduced cost compare to the alky stuff.

boost enrichment can be controlled by your bypasses, the more levels of enrichment needed the more bypasses it will require. but it will be a fine line of balancing to understand how much enrichment at what point is needed. this is why most have all there parts professionally flowed so that an absolutle number is known and calulations are made from there. as it sits, when i would use my enderle barn door injection, i had 4 nozzles in the hat and 8 below the blower with only 3 bypasses. 1 controled idle, 1 above hat for cooling and power enrichment and 1 below blower to set the main load of fuel. while it may seem like the barrel valve does all the work, each bypass will pop at your pre-set pressure and bleed threw which ever size pill you have -- to set the pressure at which your tuning for at particular speed. datalogging pressures and cracking points is extremly useful in tuning. this is why MFI is considered "on/off" since more levels of drivablity require more and more complex levels of bypass and most only set there sytem for WOT.... thus you generally only see 2 to 3 bypasses on most MFI cars.

the invention of the "select-a-jet" was one of those items that made the tuning easier as each bypass could easily be tuned with mulitple "pills" or jets on the fly quickly without having to open each bypass poppet to change the pill. something like this is worth the expense but requires a fairly good knowledge of your systems flow capability threw out the rpm range.

Flowing your pump, by a professional is one of the best moves you can make in understanding where to begin to tune or what to select for building a system.

"Fuel Injection Racing Secrets" by Bob Sazabo is a smart book to invest in if you can still find it. it will describe what you need to know so you can devlop your base on pump size to amount of required nozzles.

 

[CTX-SLPR]

I can see why he wouldn't want to mess with gas. It takes less than half as much gas as it does methanol to make the same power. With the pumps, nozzles and valves available it would be really hard to work with 1/2 as much fuel.

My system is for methanol ONLY. For gas, the possible solutions are EFI or a blow through carb.

Thanks,
Travis Quillen

Don't ask me why, it's just what he said...

gas should be easy, as it will take less parts and smaller parts to flow the needed amount of fuel and with reduced cost compare to the alky stuff.

boost enrichment can be controlled by your bypasses, the more levels of enrichment needed the more bypasses it will require. but it will be a fine line of balancing to understand how much enrichment at what point is needed. this is why most have all there parts professionally flowed so that an absolutle number is known and calulations are made from there. as it sits, when i would use my enderle barn door injection, i had 4 nozzles in the hat and 8 below the blower with only 3 bypasses. 1 controled idle, 1 above hat for cooling and power enrichment and 1 below blower to set the main load of fuel. while it may seem like the barrel valve does all the work, each bypass will pop at your pre-set pressure and bleed threw which ever size pill you have -- to set the pressure at which your tuning for at particular speed. datalogging pressures and cracking points is extremly useful in tuning. this is why MFI is considered "on/off" since more levels of drivablity require more and more complex levels of bypass and most only set there sytem for WOT.... thus you generally only see 2 to 3 bypasses on most MFI cars.

the invention of the "select-a-jet" was one of those items that made the tuning easier as each bypass could easily be tuned with mulitple "pills" or jets on the fly quickly without having to open each bypass poppet to change the pill. something like this is worth the expense but requires a fairly good knowledge of your systems flow capability threw out the rpm range.

Flowing your pump, by a professional is one of the best moves you can make in understanding where to begin to tune or what to select for building a system.

"Fuel Injection Racing Secrets" by Bob Sazabo is a smart book to invest in if you can still find it. it will describe what you need to know so you can devlop your base on pump size to amount of required nozzles.

Thanks for the advice, I'll see if I can't find that book. I understand what you are saying which is why I'm considering a reactive mechanical system like the K-Jetronic for the boost enrichment. I can't run an electronic system so looking at the mechanical stuff. I wouldn't use the restrictive air door setup and it wouldn't be for primary fueling, just an add on fueling based on boost.

However I've got a rotating assembly problem that I thought I had licked that I need to mess with for a while before I can turn my attention back to this. In any case I'll run it NA to start with to get the hang of tuning and doublechecking the parts work well together.