Dixit

iTrader: (1)

Well I used the spreadsheet and got the following numbers to use for 60# injectors, so I put these values in and cranked the car and it ran fine, after a short drive (after resetting the fuel trims) My Fuel trims were a good +20. Also while driving noticed it would buck/hesitate just slightly on the deceleration and upon accelerting it would kinda jerk once/twice before it got into moving.

Now I ended up playing around and scaling the injector table and got it down to about these values

Now its much closer to what my fuel trims were before I removed the stock 02 Z06 injectors and replaced them with the 60# mototrons. Am I doing something horribly wrong on the scaling? I searched around and found no one with 60#s on the HPTuners repository.

Dixit

jub jub

Looks like what my spreadsheet came up with at 58 PSI.

69.2833
69.7150
70.1442
70.5707
70.9947
71.4161
71.8351
72.2516
72.6658
73.0776
73.4871
73.8943
74.2993
74.7022
75.1028
75.5013
75.8977

What pressure are they rated at?

5 Liter Eater

iTrader: (5)

Was this the only change made (60# injectors)? What were your fuel trims before the injector swap?

I know someone who has 60# Motrons on his A&A Procharged vette and his IFR table looks like this:

62.43946 62.87350 63.24554 63.61757 64.05161 64.29963 64.73367 65.10570 65.53974 65.91177 66.28380 66.53182 66.96586 67.39990 67.64792 68.01995 68.39199

Not sure if those #'s came from the injector spreadsheet or what. What PSI are the Motrons rated at? If I use 43.5 I get the numbers you originally got.

If this was the only change it would make sense to scale the entire IFR up or down until the fuel trims fall back into line. I like to use the spreadsheet though. Not sure why it is not acting right with the numbers from the spreadsheet if the rated fuel pressure is right. The only thing I can figure is they are rated at 4 bar (58 PSI). Try running them with an IFR of 60# rated at 58 psi running at 58 psi.

Dixit

iTrader: (1)

Yeap that is the only thing I changed. I remember seeing a post of "gameover" who said that he went from stock injectors to 60#s and his fuel trim didnt change.

Im not sure now if I should use the first set of values and basically have to redo my entire VE and MAF table or should I just scale the Injector table till the trims get back inline. Before I did the swap the Ltrims were between 0 and -4, idle was normally around -2, after the injector swap it was sitting around +18. These are rated at 43.5psi.

Dixit

FigsZ28

iTrader: (70)

I just changed over to Mototron 60lbers and my IFR table is dam near identical to the first one you posted, and my fuel trims stayed the same.

RedHardSupra

iTrader: (1)

go with the first table, as long as your fuel pressure is 58psi, if not, recalculate using the spreadsheet from the stickies

Dixit

iTrader: (1)

Its looks fairly close to 58psi from what Im seeing on my onrail fuel pressure gauge. So if I go with the first table, Im going to need to redo my fuel trims and MAF and PE, just wanted to make sure about that. What a pain thats going to be.

Dixit

JMBLOWNWS6

iTrader: (17)

That is what I came up with Dixit. Which you can see its close to your first one. And this sheet is not a free sheet on the net. I got it from a dam good tuner. But his numbers are just as close as the free one

69.293976
69.742964
70.191954
70.640942
71.089932
71.389259
71.838247
72.287237
72.736225
73.035551
73.484539
73.933529
74.382517
74.681844
75.130834
75.579822
75.879149

Dixit

iTrader: (1)

Well back to the original tune and time to redo the whole VE table, MAF, PE. Time to pull the wideband back out, sons of bitches..... hahaha Thought i was done. But I guess I couldnt leave the crap alone.

Dixit

FRC Tom

I have 60/69 injectors in my S/C 408 and have tuned 5 or 6 other forced induction cars recently with 60s.
Your VE hasn't changed or your intake (maf), no need to change these tables if all was good before.
When using injectors this large especially on a n/a engine you need to scale them back to bring your trims down.
This will fatten you up at WOT.
When I get it on the dyno for WOT tuning I only scale the cell or cells in the ifr table that the engine runs on top to lean it out, usually the 1st.

Table from my 408.

62.50148
57.54105
58.03709
58.34712
58.71915
59.02918
59.33921
59.71124
60.02127
60.33129
60.70333
61.13737
61.44739
61.75742
62.06745
62.50148
62.68750

Dixit

iTrader: (1)

Interesting. For those who are watching, Ive got the 60#ers in now for 2days and still having issues. I managed to get my trims inline after redoing it all in SD mode. But the car has minor issues. Let me try to explain this the best I can.

Basically lets say I just let go off the throttle and Im in say 5th gear and about 2secs later I press the throttle again and the car basically hesitates for 1sec, the front nose actually dips once. The scan shows me really nothing expect the second I press the throttle and I see it at about 20% the O2s hit the floor. Again Im not even going WOT. Just getting off the throttle and getting back on it no more than 20%.

Ive tried everything now, trimmed the injector table down to the 2nd set of values you see at the top that didnt help solve it. Ive played with the Throttle Cracker table to the point where I zeroed it out and even took it as high as 3.00 across the board, that didnt help solve it either. The hesitation/sputter is killing me. Basically the car jerks foward/backward 2 or 3 times when I get on the gas from a closed throttle position. Man I may have to pull these 60#ers back out if I cant solve this. BTW I got them on Nasty Rails. This what it looks like now.
http://turbofedmax.com/Z06vette/FAST...fastsetup2.jpg
http://turbofedmax.com/Z06vette/FAST...fastsetup3.jpg

Dixit

John02SS

iTrader: (47)

The few I've done all lined up using a IFR table like the first one you have. Any reason you went with such a large injector? Maybe that is just lil too much injector. What is the Duty Cycle on them, it has to be really low.

Dixit

iTrader: (1)

Have never really checked the duty cycle since I put them in there. You think my minimum pulse width at idle is causing the problem? But then my idle wouldnt be that good. But I still hear about people putting 60# in their setup before going to Forced Induction.

Only reason I went with them because Im planning on a LS402 build with twin turbos and wanted to get the injectors only once.

If the problem is because I have way too big of an injector for NA, Then maybe I need to swap them out for SVO 30#s

Dixit

SmokingWS6

iTrader: (1)

Seperate from the trim issue, the coasting and idle bucking could be caused by the tune not allowing for the injectors to open for a shorter time. Minimum injector pulsewidth will cause issues on large injector cars. It'll usually limit pulsewidth to 1.7ms while some cars will need to see less to achieve 14.7 or whatever your desired afr is.

Dixit

iTrader: (1)

So the stock 02 Z06 has the minimum pulse width set to 1.261 msec. I was thinking about lowering this but Im confused now on how the whole short pulse limit and short pulse adder. Seems like it can never get lower than the short pulse limit which is showing as 3.997 msec.

Dixit

cablebandit

iTrader: (37)

my 60s do the SAME thing.....let off gas and then hit...BIG lean spike and hesitation

Dixit

iTrader: (1)

Interesting.

I think I might be closer to finding the problem. Looks like a pulse width issue for sure. Heres what I see.

On my stock setup (with the stock Z06 injectors) When I would press the gas and then let off, the decel showed that the pulse width was about 1.6 msec.

Now on the 60# injectors the injector duly cycle and the pulse width is definetely alot lower than before. But heres the kicker, the same decel scenario, Im still seeing a 1.6 msec on the whole decel. So That means its throwing too much fuel and causing it to hesitate and sputter as soon as I get back on the gas cause there is too much fuel. Cause I can somewhat prove this by driving and as I row threw the gears, you got only a split second of decel as I get off the gas to shift and it almost never hesitates then. Only really happens when I decel and off the gas for a good 2-3 secs and no load (like not deceling up a hill) and then get slightly back on the throttle, it will hesitate/sputter for a split second.

Dixit

cablebandit

iTrader: (37)

mine does the same thing BUT i watch my wideband and when i hit the gas...it pegs it lean.......

Dixit

iTrader: (1)

Im looking at my scan and I can see on the decel the Short term fuel trim goes from say 0 to about -15 and during the decel and right when i get back on the throttle, you can see the short term it at -15 which gives me the inkling that there is major richness happening and causing the sputtering. I dont have my wideband hooked up, I need to get that in there again. And yes Ive turned off LongTerm fuel trims for this test to narrow down whats going on. And the 1.6 msec Im seeing proves that its gotta be throwing almost double the amount of fuel since my stock injectors were showing the same pulse width on the decel. All the other reading on my 60# ers show the pulse width half of what they were before, except this decel.

I now have to wonder is it even possible to go down to a 0.8 msec pulse width?

Dixit

SmokingWS6

iTrader: (1)

Their purpose is to protect the motor from going lean but with larger injectors its values are usually to high. I just looked over a file similar to yours. You'll need to lower the Min injector pulsewidth and Default injector pulsewidth. It may also help to reduice the short pulse adder by 20% as a start.