Suckage.

What RPM are you heading through the traps at? Does it feel like you hit a wall ever? DId you ever make sure you weren't rolling off timing at higher RPM?

 

I'm gonna read through all this again and think about whats going on. Will report later. Something doesnt seem right. I actually think a good log is not far off from a header but I'd like to think you shouldnt be running the same or worse with that turbo and that boost.

 

i would like to see the fuel issue rectified and the boost getting raised. performance staying the same at this point isnt all that big of a deal i would say. if you could get the boost up to 25+ with good fuel im sure it would pick up some more

something i would like to see on your car in the future is a pair of nice heads and maybe an accel superram or something like that? since that is an intake the heavy hitting efi cars would have had in the early 90's, it would be sorta period correct compared to the tpi.

i dont remember what you have engine-wise, but i have been considering selling my 358" sbc turbo motor. studded 4 bolt block, forged crank, manley h beams, weisco pistons. i have a set of edelbrock victor jr heads for it, and a set of afr 210 eliminator competition heads for it. hydro roller cam, tie-bar lifters.
single plane accel pro flow efi intake. never been ran.
pm me if you might be interested? im in sc.

 

I think he may have an issue with mega squirts due to the spark control and a possible voltage supply to the fuel pump problem too? I say that because he has dropped that tank many times to replace the pump, but is still having the same issue with fueling. Check the grounds and all connectors.

 

alls he has to do is set a timing map to say 25* all across and rev the engine while somone checks with a timing light , this will let him know just how far its actually off

im also wondering if he is using ait based spark retard


the last issue i can think of would be if he is using low-z injectors , i had incorrect settings on my peak and hold injectors and it would give me fueling issues from the midrange and up once things started to get warm


since u just ran the car , how much boost did it take witht he old setup to run the same times? are u running less or the same boost now to run the same times

 

All good ideas so far.

I would recommend timing checks, if its off even 5-8 degs it could be substantial power. Atleast rule that out. Dyno would be nice controlled environment for that

I'm not familiar with megasquirt but there may be settings involved with injector timing? If they arent timed right to spray, there could be some high rpm issues with fuel delivery. What injectors are you running?

Whats your base fuel pressure? With a walbro 255, do not exceed 60-64 psi at the rails with boost. I have my base fuel pressure at 39-40 psia so on 24 lbs I have seen 64 or so psia. Once you start getting over that level, delivery drops off alot, but you should have a good 500-550 whp capability with single pump. My twins supported a 1000 thru a th400.

I'm starting to think there may be something with the cam and intake not jiving. Cam should be smaller IMO with a stockish TPI top end. Else invest in some runners and big base, port them out alittle bit and make the heads the restriction. Siamesed runners to push peak hp rpms to 5500+ should help.

Or try advancing cam 4 deg to close intake valve sooner. May help hold cylinder pressure more, but becareful on the timing, back off a few degs and work back up.

You could also be peaking performance of those heads to the point that small changes in boost like 14 to 17 doesnt pick up any power if only a little bit. My old combo didnt seem to pick up much power after 15 psi. My new combo isnt limited anywhere and is a solid 30-33 whp per lb boost increase all the way to 24. I'll look up your turbine spec as well, but turbo shouldnt be holding it back. 94mph traps is 400-450 whp depending on weight.

 

the ms he is using doesnt have injection timing events per say , but u can set it up to fire all 8 inj at once 1-2-4 times per complete cycle of the engine

or u can alternate in banks of 4( left -right) 2-4-8 times per complete cycle etc

im thinking the injectors may be getting hot and starting to shut down when it needs a longer pulse width

im also curious about a possible voltage drop at the pump or injectors when rpm comes up

 

That's good MS can do that with the injectors, but if his injectors are to small then it will surely cause the injectors to get hot especially if he is commanding them to open more than once per cycle.

ZZ3Astro, what size injectors are you running and what's the duty cycle at WOT?

 

gone

 

I would start there...

 

gone

 

Is there a Inverse MAT Term Lookup Delta Multiplier vs. Airflow table to compensate for commanded AFR at WOT? I know MS is a stand alone system, but does it have a learn capability like factory ecm's (ie Open Loop and Closed Loop). I say that because I remember when I moved my intake air temp sensor to a cooler spot on the intake tubing I had to change the settings in that table to compensate or it will be lean at WOT.

It's starting to sound more of a tuning issue IMO.

 

No Steve, I mean start there. Your running 37-psi base, try raising it to a tad over 40-psi base (adjust your VE down low to compensate), which is normally where it should be when upwards of 18-psi of boost...

 

gone

 

There is a nice writeup by Vader on how to convert your stock fuel pressure regulator to an adjustable unit, either that or just pull the FPR cover and put a quarter in there to increase your pressure just a tad. Lots of guys are losing fuel pressure above 15-psi running the stock regulators, and even with the adjustable BBK's for that matter. Most of the Kirban regulators that I see are running a tad over 40-psi base on anything in the sub-eleven second zone. My setup is at 42-psi (unhooked), and I have had it up to 20-psi of boost during a test run, and the fueling remained solid. It's obviously just a suggestion Steve, so take it like a grain of salt...

 

I wouldnt be using a stock regulator under boost. I would go aftermarket boost referenced, and maybe even log fuel pressure using a common sending unit like holley or autometer's unit

 

switch the fueling to 2 squirts alternating , this will fire each bank 1 time per cycle , do not put 1 squirt alternating or one bank will never fire

1 squirt simultaneous is not recommended for anything with high hp specially with large injectors , it causes a fuel pressure drop at the injectors

 

This is why I say something is wrong with the tune. First is your seeing 75.6% duty cycle for those 65lbs. injectors which indicates something is going on with the Injector PW vs. Battery voltage table.

I'm saying this because I have 42lbs. Injectors on my NA 383 and looking back on my data log, 1/8 mile pass using datamaster I've seen 78% duty cycle and 6.84 PW. On that pass I went 7.28 @ 94.95 MPH, 1.54 60ft. My car runs 7.3's all day on motor. Just think about it 75.6% DC 65lbs inj vs. 78% DC 42lbs. inj?? It's been dynoed once about 3yrs ago making 461 RWHP on motor and 598 RWHP on a 150 shot before the nano. I know my car is NA and yours is boosted so it's like comparing apples to oranges, but as far as tuning goes the duty cycle tells a story too. And that is if you have enough injector to continue to make the power. In your case yes 65lbs. should be fine, but your data is saying differently. It's in the tune man, take a closer look at the settings in your tables.

 

i agree duty cycle is to high for the power its making with 65# injectors

switching the fueling to what i said earlier should help im betting that he is running out of fuel inside the rails and having to add more and more fueling to get longer pulse widths to get the correct amount of fuel in the engine


when firing all 8 injectors at once the fuel presure drop is so sudden it will never show up on a gauge but it will have a huge effect on afrs and fueling

its even in the ms manual that 1 squirt simul injection is not recomended


now the fact that it runs ok when its cold has me a lil concerened, but leaves me to belive the fuel is starting to boil in the rials or air is being introduced into the system when warm


first things first i would fix the fueling settings and go from there

 

That explains a lot man. By no means am I a MS user expert, but its always something simple that we overlook.

 

I agree. Should be running all 8 fire every crank cycle. Engine cycle creates too long PWs. I don't know why MS offers this except as a crutch for getting idle to work with large injectors. I have always thought that MS should switch to engine cycle firing below a certain RPM, and double fire at higher RPMs. This would solve the high RPM fuel problem and low RPM problem with large injectors and bank/batch fire.

Overall, change it to twice per engine cycle (once per crank) and go from there. With all the testing you have done it points to the ECM or wiring or ECM setup or combination. Maybe even an MS hardware problem......solder joint, wrong HW config, etc.

 

1 squirt simul works on lower power na engine but once u get into large injectors and hogh hp engines it can cause issues


for his app 2 squirts alternating or 2 squirts simul will work , i recomend 2 squirts alternating as does everyone else

 

gone

 

im not 100% sure this will fix ur issue but its a deffinate step in the right direction .

by all rights with the fueling the way u have it u should have the issue hot or cold

my thoughts on this is ur fuel systems capability to keep fuel inside the rails at proper presure with all 8 injectors firing at once is on the very edge

i do relize u have a dual feed setup , do u have the crossover tubes in the fuel rails enlarged?

i wish i knew the internal volume of the stock rails , and exactly the size of the fuel inlet and the crossover tubes ( very small) so we could calculate just how much volume they can actually flow

 

gone

 

gone

 

Very interesting, I think we're coming back to learning the car in a way. Any chance you could get some race gas and start messing with the higher RPM WOT timing? If you hit 20 PSI on pump without signs of detonation that is somewhat interesting as I would have thought you'd have started seeing issues considering it's a fairly stock ZZ3.

Also did you degree the cam? Somewhat of an odd question but figured I'd ask especially if it got a different timing set.

Hell I'm surprised the old L98 isn't getting rings/bearings and going back in at this rate.

 

can You post your msq file ?

best regards

 

Hit 24 psi on mine no issues when air inlets are 40's deg. Thats helping him out plus the cam being bigger is lowering dynamic a good bit. Motor is a boost junky lol

Yeah it should have some ***** but throw some good heads and intake on that motor and watch magic occur

 

x2. it would pick up like 200hp lol

 

im not surpised he has no detonation at 20 psi specially in this cold air , i was 20+ witht he iron heads and no detonation with less spark timing them him

with that 700r4 he is loosing somewere around 25% so its prolly making alot more power then he thinks

 

gone

 

well its good to know the fueling setting changed looks to have solved the lean out issue

 

gone

 

Good to hear things are working out. Can't wait to see some good track results, it's way over due for you!!

 

Anxious to see the results man!!

 

...on the edge of my seat...

 

 

Let's hear some good news!?

 

gone

 

do u have a infared temp gun? check fuel rail temps , and lines comming off the frame?

my only thoughts are
#1 boiling the fuel
#2 getting air in the fuel system
#3 bad pump
#4possibly wiring to the pump getting hot and resistance going threw the roof causing a voltage/amperage drop to the pump

i would check number 4 first rig up a multi meter in view and probe for voltage drop and or restiance changes in the wire

what fuel filter are u using? if its a stocker type how about pulling it off and putting a piece of rubber line in its place just for testing

 

Just try the fuel pressure regulator Steve. Was talking to a few MAGNA guys I know and they agree, and say the same thing, that if you have no fuel at higher boost levels, and that you confirmed a fuel pressure drop, and your convinced that it is not the pump, then it has to be your fuel pressure regulator. If the fuel was vaporizing in the rails then the engine would shut down because the injector can't fire vapor. You have nothing to lose by upgrading the fuel pressure regulator, so just do it and be done with it already. By the way, I would stop messing around with your timing until your fuel is dialed in completely. Again, take it like a grain of salt...

- Rob

 

gone

 

what size feed/return lines? is the tank vent working properly?

this reminds me of a friend's car that would boil the fuel in the tank sometimes. (i know!) i drove the car once and it gradually choked itself down. got out of the car and i heard a suction sound coming from the gas cap and boiling water sound in the tank. i loosened the cap a bit, and it started to whistle like a tea kettle. i backed away from the car until it stopped. lol i believe he said the problem was the pump?

 

Steve, we just watched your latest video. I won't post the video, I will leave it to you to post it because it is your video and thread. However, now that we can SEE what is taking place with the pressure drop, my Grand National buddy and I want to point out a few things. For starters, contrary to what I was writing above, it more than likely isn't your fuel pressure regulator unless you are not running a zippy tie or some type of secure on the vacuum line that regulates proper boost. This also goes for the boost gauge, because if it isn't zip tied or secured you could be running way more boost than you really are while reading less, and if your not tuned for it, it will of course go lean. Second, you said you are running the fuel pump directly off of the battery, right? What size wire gauge are you running from the battery to the back of the alternator? You could be losing voltage that way if the gauge is too small. Third, don't assume that your fuel pump can handle the extra boost just because it is sold that way, it is either dying off because it can't handle the volume, could be a bad pump, or perhaps even your fuel lines are kinked somewhere. Bottom line is, when you see 12.0 afr at that boost level, let go! Don't wait until 14.0 when testing fuel pressure...

- Rob

 

At this point the frustration level would have me ripping entire fuel system out and starting new. Sorry to hear you still have issues. I never experienced any of that before so i am at a loss. If regulator has been changed then i am not sure what could be wrong

I would run fuel pump power off alternator post for highest voltage

 

yeah im betting its a voltage/amperage drop at the pump , or a pump thats no good

go grab 2 190lph airtex pumps off ebay for 12$'s each and drop them in and see if the problem persists , that would be the cheapest way i could think of to swap pumps to see if the issue goes away. i have 3 of those pumps in the tank of my tt iroc they work great, but if it turns out that solves the issue , u could always just go buy a 340lph or 400lph pump


if the issue stays its a volt/amp/resistance issue somewere in the wiring

 

gone

 

You have two wiring problems.

1) In order to race and for your own safety, a rear mount should have a cut off switch and a dedicated alternator wire running from the alternator to the switch.

2) Earlier you posted that the fuel pump is powered from battery through a relay. Now you posted about a DC-DC converter powering it. That is a problem. Remove the DC-DC converter. V vs I curve will drop under load (more fuel required) and vs run time (heat generated). I would not trust the DC-DC converter for this application. If you want more voltage to the pump then run some proper sized diodes from the alternator battery terminal to the Vsens terminal. Run the car off the low side of diodes and the pump off the high side of the diodes. DC-DC converters not a good idea unless you design it youself. Just another failure point.

 

gone