Over the winter I made some changes to my SBC. It’s a 421 ran 6.15 in my nova with a 1475 terminator with 0 pump, 32 nozzles, 84 bypass. We upped the compression from 13-1 to 15-1 added a dry sump oil system and a Hogan’s intake with 2 1475 Terminator’s. I decided to do some research on people that flow injection and picked what I thought was a good company from reviews to flow the system. He said the 0 pump was boarder line to small and gave me a setup to use 33 nozzles, 54 bypass to come up with a 5.1 AFR. Previous dyno with a 1050 alcohol carb was 680 at 6600. Friday we put it on the dyno with the setup provided and the fist pull it made 648 at 6100 and lost power from there. We decided to riches to a 50 bypass and stayed the same so we started leaning and ended up 600 at 6100 with a 32 nozzle and 78 bypass. Through all the changes the EGT was 1050 to 1075 so no matter how much we moved it it wouldn’t respond in the EGT. We have decided to install 36 nozzles and 100 bypass to riches and see if it’s just to lean. One thing the flow guy said that has stuck with me is a motor can be so lean it won’t make power, wont look lean on the plugs, won’t melt anything or make any heat. I haven’t callled the guy that flowed because I never trusted the tuneup or most of the things he was saying. Ron’s says the 0 pump is fine and a 35 nozzle with 86 bypass should work fine. Trying the 36 because we don’t have 35s. My question is have you seen a motor so lean it would act like this on the dyno

Yes and why can’t you change the pulley ratio a little bit.

If needed the pump can be speed up.. just trying to get it somewhat close and to make power. After I get it in the car where I can log fuel psi and 02s I should be able to get it tuned

I am surprised you can’t log that stuff on the dyno.

Fuel psi can be. The dyno is old so doesn’t have all the bells and whistles on it

I don’t think the pump is the issue just the nozzles are to small to get enough fuel in the motor but still can’t rule it out. Some friends are running the 0 pump on 800 hp bbc and we are shooting for 750 on the sb

Same issue I have, SBF. Have not had a chance to get back to the track with a 1/2 pump yet. Hopefully soon. Same deal, always goes lean with RPM and falls off above about 6600. 14.9:1 438" windsor. 0 pump 36 nozzles 50 pill and WB02 still shows it leaning out above 6500 or so. I have a 1/2 pump on it now and will mess around with it if it ever quits raining. Running "normal" (lean) it repeats timeslips at 5.80-5.85 depending on the weather; I'm assuming based on car weight of 2600, should be around 700hp give or take. Rons said the 0 pump was likely borderline and that perhaps speeding the pump up a little might help, however I found this BNIB 1/2 pump for sale locally; fresh from Rons and cheap enough to try it instead.

I have a smaller pump pulley I’m taking back to the dyno tomorrow and will try it to speed the pump up if the nozzles help but don’t fix the issue. Maybe going with the dual terminator setup I need the 0/12 pump. I know it was to much with the single but more air means more fuel

I had Steve Casner of CRE flow my fuel injection and I thought he did a great job. I don't know if he is doing it anymore since he is so busy with the transmission stuff but you might contact him. Good luck!

I won’t say who flowed mine but I wasn’t real happy when I got it back. 7 nozzles were within 1.2% and 1 was almost 3% and he didn’t fix it. The tune seems to be way out in left field so I think my choice was very bad in getting this done with who I used.

how is the supply side to the pump setup on the dyno? And i would have the fuel PSI logged, it will tell you if your changes are working.

Joe

Fuel tank is on a cart and sitting right beside the engine. Sits a little higher than the pump with a -10 hoseWe checked the tank and return even though the engine that came off the dyno when mine went on was a 496 with a terminator we still checked it.

Ok, I decided to run your numbers based on a 4.5 GPM pump “-0”. A 421 with 105% VE at 60 degrees, 0% humidity at 29.96 Barometric pressure.
With a 33 nozzles and a 54 pill your a/f would be 3.73
With a 32 nozzle and a 78 pill your a/f would be 5.09
With a 36 nozzle and a 100 pill you’re a/f would be 5.83
With a 35 nozzle and a .086 pill you’re a/f would be 5.13
With a 36 nozzle and a .086 pill you’re a/f would be 4.99
Like I said, this is all base on a pump that pumps 4.5 GPM at 3500 RPM

Joe

This message has been edited. Last edited by: sr4440,

According to the sheet I got when flowed
3.55GPM @4000@100 psi
54 pill only 8000 @ 2.55 GPM

He’s also got the VE at 118%

With a 3.55 pump
With a 33 nozzles and a 54 pill your a/f would be 4.82
With a 32 nozzle and a 78 pill your a/f would be 6.58
With a 36 nozzle and a 100 pill you’re a/f would be 7.53
With a 35 nozzle and a .086 pill you’re a/f would be 6.63
With a 36 nozzle and a .086 pill you’re a/f would be 6.45

Joe

Also I’ll add if they print it up to 4000 on the dyno the motor sounds like your on/off the throttle like it’s starving for fuel

With a 3.55 pump and 118VE
With a 33 nozzles and a 54 pill your a/f would be 5.32
With a 32 nozzle and a 78 pill your a/f would be 7.25
With a 36 nozzle and a 100 pill you’re a/f would be 8.31
With a 35 nozzle and a .086 pill you’re a/f would be 7.31
With a 36 nozzle and a .086 pill you’re a/f would be 7.11
Might I suggest you get a new pump.

Joe

I’m going to change pulleys first thing with the 33/50 back in it and see if it picks up HP and try’s to rpm. If it does then I’m going to order a pump. If need be I could 1-1 the pump to see if that’s the issue. I have an APD pump and could call to see if they have any flow bumped on them and try it

your 36 nozzles with your 54 pill gets you a 5.09 A/F.


Joe