3 litre wolf efi crankcase injected 3 litre build

[mrcrsr]

charly, i understand what you are saying about blade area, we could say in that case, currently at 1/4 throttle the rpm is the same as before at half throttle. that would be a good way to compare the difference. but irreguardless, at 3 k rpm, between both intakes, fueling went up. so i am looking at this from a steady state 3k rpm-why would fueling go up ? it takes a certain amount of air to get the engine to go 3k rpm, and the fuel amount should be the same, so i'm trying to understand this as it doesn't make sense.

[Chaz]

OK , lets use your numbers .. and a couple more that I'll just round off to the nearest whole number.
Lets say your TPS has a key on range of 1 to 5 volts much like a stock ignition / fuel management system .

If you rode along at half throttle putting out 150 hp . The motor would require 75 lbs hr of fuel and 300 cfm of air to support a .5 BSFC ... and to provide that , the ECM would read 3000 RPM and 3 volts.

Now install an "aggressive early" air valve that provides the same 300 cfm at quarter throttle. Without changing anything else .
Wouldn't the ECM be seeing 1.5 volts, and because of that , provide 37.5 lbs / hr of fuel... ?

My point has been from the start, that the fuel at a quarter throttle need's to match the old half throttle settings. And continue to rise untill something else down the line becomes the governor in the system and then at that point the fuel load needs to be trimmed back to match the engines ability to move air ... My head hurts now .. LOL

[vnemous]

Check the fuel pump maybe the grommet looks like this

[Todd D]

So basically it sounds like you need to take the values from your old curve at say 3000 rpm and move them down to 2000 rpm on the new furl curve you are writing.

[PanRonnie]

I don, t think that, s what he means
I think he means that if we assume all things being equal it takes a certain amount of horsepower to push the boat through the water at 3000rpm
It took a certain amount of fuel to do that with the old intake
And now with the new intake fuel consumption went up to get to the same rpm (Hp)
The way i would explain it is that the engine (intake) is less effecient at that rpm with the new intake in turning fuel into energy (thermal effinciency)

[Todd D]

I was just trying to give him a base line fuel curve since he has the Wolfe electronics he has to build it. He had it setup pretty good with the horn. Basically if he finds a spot In the curve that is 13-15% richer than where he's starting to have problems it will be a base line to modify. He might have to increase each value exponentially because the new throttle blades are xyz times bigger at each percent that the blades rotate open.

[mrcrsr]

I don, t think that, s what he means
I think he means that if we assume all things being equal it takes a certain amount of horsepower to push the boat through the water at 3000rpm
It took a certain amount of fuel to do that with the old intake
And now with the new intake fuel consumption went up to get to the same rpm (Hp)
The way i would explain it is that the engine (intake) is less effecient at that rpm with the new intake in turning fuel into energy (thermal effinciency)

exactly what I'm trying to understand

[Todd D]

I wouldn't say it is less efficient because all things things aren't the same when you're comparing values at certain rpms or tps values. When you add more air you must add more fuel to keep the thermal temps in the correct range. But what we have now is that at say 3000 rpm the motor is effectively getting the same amount of air as it was at WOT. So you must add more fuel to cool the burn. I understand that the boat isn't running the same at 3000 rpm now as it was at WOT before but that's because things like timing are lower. I think what charlies really trying to get across is that the intake isn't correct for these motors the throttle blades are just too large. Basically that intake makes this motor a 2 speed.... idle and WOT. There is nothing in between and nothing after. The reason I say nothing after is at say 3000 rpm you have introduced all the air the motor can handle because something else is restricting the flow. Like the cages, goose neck in the block at the sleeves, exhaust chest or tuner......

[mrcrsr]

i hear you todd, but my point is, to get the boat to run 3k rpm, it takes a certain amount of air, irreguardless of throttle position, so the mad may be at 1/8 throttle, the horn at 1/4 throttle(these are hypothetical numbers). so if u are still requiring the same amount of air to do the same job shouldn't it require the same amount of fuel? and like said earlier, i am injecting fuel after the reeds, so that should take disrupted air flow out of the mix(if it was wet reed i could understand it). todd, also, being crankcase injected, should free up almost 10% airflow thru the reedcages(if u consider at wot air/fuel mix is amost 10 parts air,1 part fuel. injecting after the reeds should give more room for airflow thru the cages)

[PanRonnie]

i think the plenum intake is simply more efficient at lower RPM
maybe because of the plenum design, an intake pulse or simply the longer intake runner
now this is not really a problem as long as the MAD intake outperforms the plenum design at higher RPM
long intake runners build torque short ones build horsepower
provided it is matched to the breathing through the engine ( Hot cam four stroke, higher porting 2 stroke )
so you should see better numbers at the higher rpm,s hopefully

[Liberator*21]

i hear you todd, but my point is, to get the boat to run 3k rpm, it takes a certain amount of air, irreguardless of throttle position, so the mad may be at 1/8 throttle, the horn at 1/4 throttle(these are hypothetical numbers). so if u are still requiring the same amount of air to do the same job shouldn't it require the same amount of fuel? and like said earlier, i am injecting fuel after the reeds, so that should take disrupted air flow out of the mix(if it was wet reed i could understand it). todd, also, being crankcase injected, should free up almost 10% airflow thru the reedcages(if u consider at wot air/fuel mix is amost 10 parts air,1 part fuel. injecting after the reeds should give more room for airflow thru the cages)

Charlie,

Just came back from 2 week vacation and saw your post. Let me share what I have experienced first hand.................

No expert here, but my hands on experience with the TPS/MAD intake is that running the TPS 1:1 against the throttle opening in the MAD doesn't work period, creates a lean condition (more air/less fuel) due to throttle blade opening volume, EGT's confirm that. I altered the advance ratio on the TPS through 1/2 throttle (meaning that at 1/2 throttle TPS was sending "FULL" throttle output signal to the PCM) and the results were spectacular, motor ran and pulled very hard, but now I'm working on making the top end run the same by adding extra fuel via 6 more fuel injectors. I'm still in the build stage on my project, but everything I've done and tried dictated the need for additional fuel. Hope to be on the water by the end of the month and I'll let you know how it goes. Good luck on your end.

[mrcrsr]

good to see you back gary! i think for now i am going to put the horn back on it, river ranch is 3 weeks away, and i haven't had the time to reassemble the engine yet, so it will be a time crunch to get the boat back together and running by then, and maybe put a couple of hours on it

[Liberator*21]

Have a great time at R/Ranch. I'll let you know what and when on my results once I get out (probably end of the month).

[mrcrsr]

skater has been running great, got 40 hours since the rebuild. i am going to go back to the mad efi intake and retune for it soon. i've been working on some other engines, between the camaro and customers engines. i am going to start a thread with a 250 3 litre i just put together. take a look, this is a more production based engine with some mods.

[PanRonnie]

already tried running closed loop?
it,s good fun



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