60 lb injector swap on Radix 2004
05-06-2005, 12:05 PM
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60 lb injector swap on Radix 2004
Very interesting findings. I will post them later today after I get the write up all worked out and coherent. The results were very successful but not exactly what I expected. I WAS out of injector with the 42's.
Cory
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05-06-2005, 12:12 PM
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You are not the first i have heard say that w/the radix. Have you read the thread over on silveradoss.com. There is a long discussion about that.
05-06-2005, 12:13 PM
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What i dont understand, is that i was under the impression that it is working ok for the procharger and sts guys. I dont have any evidence either way though.
05-06-2005, 12:19 PM
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Originally Posted by CHarris
Very interesting findings. I will post them later today after I get the write up all worked out and coherent. The results were very successful but not exactly what I expected. I WAS out of injector with the 42's.
Cory
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05-07-2005, 01:31 AM
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For those who don’t recall my last setup, I had 42 lb injectors and a fuel pump voltage booster and they were leaving me a bit lean on top end of the RPM band. Here’s the short history…
42 lb injectors WITHOUT the voltage booster I saw this-
1st gear- AFR: 11.0 - 12.6 (with 23.8 ms injector on times)
2nd gear- AFR: 11.0 - 12.7 (with 23.8 ms injector on times)
42 lb injectors WITH the voltage booster I saw this-
1st gear- 10.9 - 12.1 AFR (with 23.8 ms injector on times)
2nd gear- 11.0 - 12.1 AFR (with 23.8 ms injector on times)
Clearly, the voltage booster was helping out a lot but was not able to keep up with the AFR I wanted (11.1 - 11.3).
Now, the 60lb injectors WITH the voltage booster gave me this-
1st gear- AFR so rich it would miss and not run right at all.
2nd gear- Same.
60lb injectors without the fuel pump voltage booster gave me this-
1st gear- AFR 10.9-11.2 (with 13 ms injector on time)
2nd gear- Same.
The extra AFR allowed me to run more timing again and not have any fear of burning parts. With the 60’s I have lots of room for growth without having to buy injectors again. I definitely would not recommend these to a novice tuner. You will have a hard time getting these to work right- if you even succeed.
Getting the 60’s to run right was a serious challenge. We expended about 15 hours and 18 gallons of gas getting it right. We tried several approaches and ran into issue after issue. If the injectors would idle good- PE was fouling the plugs. If PE was good- part throttle drivability was crap. We tried scaling the VE, scaling the injector constant, scaling the MAF. Nothing worked quite right. This took many hours.
Finally, we put 72’s in the injector constant (because the Motrons are rated at 60 lbs on a 3 bar system), ran several logs of MAFless VE tuning. Got that nailed, then went on to scaling the MAF to make it stop adding fuel. The MAF required targeted scaling based on MAF Frequency logs because it needed more scaling in the lower regions than the upper.
We finally realized (well, I didn’t, but Jimbob did) that the problem was the big injectors were puddling fuel. Puddled fuel is interpreted as a lean condition by the PCM and the logging software makes you think that you have to add fuel when you should have taken fuel away. You end up overshooting and chasing a moving target.
These Motron 60’s are idling at 1.8 - 1.9 ms, which is pretty small considering that the 42’s idled in the 4 ms range. That says a lot about the quality and ability of the Motrons.
To install the 60’s I followed guidance I found on Silveradoss.com that told me to buy the car type injector plugs (got mine from the sponsor Speartech) get 5/8 longer bolts (the ones I bought from Home Depot were 6mm x 30mm) and some tubing to make a 5/8 spacer for every injector bolt (bought aluminum tubing from Lowe’s). It takes six bolts by the way.
The install of the injectors was fairly easy and straight forward. The only issue or question was about how to splice in the new injector pigtails. I took the truck plugs apart and saw that it was labeled “A” and “B” so I mated the appropriate wire on the harness to the new plug wire labeled “A” and “B”. I left about 3 inches on each pigtail so there was plenty of wire left to return to stock if necessary.
I firmly believe that the 42's are fine for all the guys with pre-2004 trucks. You guys have a fuel pressure regulator that gains pressure as boost increases. That makes your 42's seem a good deal larger under boost conditions. The 2004 does not build pressure in the same way. I took measures to ensure that flow did not drop off with the voltage booster, but I could not control pressure which must have been falling off at the high RPM region. With the 60's I have so much injector available that a drop in pressure has no effect on my system. I don't know what the 2004 reaches for pressure at wide open throttle or under boost conditions. I do know that I have 58 psi at idle.
I highly recommend consideration of the fuel pump booster for guys trying to stretch the 42's a little farther. You can see how it worked for me above. However, ff you've got 60's on, you had best leave it alone. I expect I'll sell mine since I can't use it any longer.
It's a bit long but there it is. All laid out nice and neat... sort of
42 lb injectors WITHOUT the voltage booster I saw this-
1st gear- AFR: 11.0 - 12.6 (with 23.8 ms injector on times)
2nd gear- AFR: 11.0 - 12.7 (with 23.8 ms injector on times)
42 lb injectors WITH the voltage booster I saw this-
1st gear- 10.9 - 12.1 AFR (with 23.8 ms injector on times)
2nd gear- 11.0 - 12.1 AFR (with 23.8 ms injector on times)
Clearly, the voltage booster was helping out a lot but was not able to keep up with the AFR I wanted (11.1 - 11.3).
Now, the 60lb injectors WITH the voltage booster gave me this-
1st gear- AFR so rich it would miss and not run right at all.
2nd gear- Same.
60lb injectors without the fuel pump voltage booster gave me this-
1st gear- AFR 10.9-11.2 (with 13 ms injector on time)
2nd gear- Same.
The extra AFR allowed me to run more timing again and not have any fear of burning parts. With the 60’s I have lots of room for growth without having to buy injectors again. I definitely would not recommend these to a novice tuner. You will have a hard time getting these to work right- if you even succeed.
Getting the 60’s to run right was a serious challenge. We expended about 15 hours and 18 gallons of gas getting it right. We tried several approaches and ran into issue after issue. If the injectors would idle good- PE was fouling the plugs. If PE was good- part throttle drivability was crap. We tried scaling the VE, scaling the injector constant, scaling the MAF. Nothing worked quite right. This took many hours.
Finally, we put 72’s in the injector constant (because the Motrons are rated at 60 lbs on a 3 bar system), ran several logs of MAFless VE tuning. Got that nailed, then went on to scaling the MAF to make it stop adding fuel. The MAF required targeted scaling based on MAF Frequency logs because it needed more scaling in the lower regions than the upper.
We finally realized (well, I didn’t, but Jimbob did) that the problem was the big injectors were puddling fuel. Puddled fuel is interpreted as a lean condition by the PCM and the logging software makes you think that you have to add fuel when you should have taken fuel away. You end up overshooting and chasing a moving target.
These Motron 60’s are idling at 1.8 - 1.9 ms, which is pretty small considering that the 42’s idled in the 4 ms range. That says a lot about the quality and ability of the Motrons.
To install the 60’s I followed guidance I found on Silveradoss.com that told me to buy the car type injector plugs (got mine from the sponsor Speartech) get 5/8 longer bolts (the ones I bought from Home Depot were 6mm x 30mm) and some tubing to make a 5/8 spacer for every injector bolt (bought aluminum tubing from Lowe’s). It takes six bolts by the way.
The install of the injectors was fairly easy and straight forward. The only issue or question was about how to splice in the new injector pigtails. I took the truck plugs apart and saw that it was labeled “A” and “B” so I mated the appropriate wire on the harness to the new plug wire labeled “A” and “B”. I left about 3 inches on each pigtail so there was plenty of wire left to return to stock if necessary.
I firmly believe that the 42's are fine for all the guys with pre-2004 trucks. You guys have a fuel pressure regulator that gains pressure as boost increases. That makes your 42's seem a good deal larger under boost conditions. The 2004 does not build pressure in the same way. I took measures to ensure that flow did not drop off with the voltage booster, but I could not control pressure which must have been falling off at the high RPM region. With the 60's I have so much injector available that a drop in pressure has no effect on my system. I don't know what the 2004 reaches for pressure at wide open throttle or under boost conditions. I do know that I have 58 psi at idle.
I highly recommend consideration of the fuel pump booster for guys trying to stretch the 42's a little farther. You can see how it worked for me above. However, ff you've got 60's on, you had best leave it alone. I expect I'll sell mine since I can't use it any longer.
It's a bit long but there it is. All laid out nice and neat... sort of
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05-07-2005, 03:13 AM
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UMMMMM....they were 10X more of a pain in the *** to get right...
Way different fueling then the prior 36lbs (42lbs at 4 bar). It took some big VE tuning (as in way lean then way rich then way lean again, and everything in between) to get right, we don't even want to talk about the transitional fuel AFR from Boost to PE mode issues, along with the strangest MAF table. I don't think I would like to tune a customers car/truck with these. To much chance of frying something or washing the cylinders (Big Cam car or stroker would work these injectors and give better resolution, though). Lucky Cory just wants to get it right...
These injectors due kick ***...but...a big warning to any novice tuner expecting to just rescale the IFR tables and expect them to be even remotely close. Cory's happy...I'm happy...the world is back on axes again
and yes they are loud....like lifter tick, almost. "That just tells you there working, right"
Jimbob
Way different fueling then the prior 36lbs (42lbs at 4 bar). It took some big VE tuning (as in way lean then way rich then way lean again, and everything in between) to get right, we don't even want to talk about the transitional fuel AFR from Boost to PE mode issues, along with the strangest MAF table. I don't think I would like to tune a customers car/truck with these. To much chance of frying something or washing the cylinders (Big Cam car or stroker would work these injectors and give better resolution, though). Lucky Cory just wants to get it right...
These injectors due kick ***...but...a big warning to any novice tuner expecting to just rescale the IFR tables and expect them to be even remotely close. Cory's happy...I'm happy...the world is back on axes again
and yes they are loud....like lifter tick, almost. "That just tells you there working, right"
Jimbob
