travis1746

Went to the dyno today to get some tuning done and came away with some questions that I would like some opinions on. I have a 2006 Z, ecs 1500sl kit, headers, fast 102, NW 102 throttle body, aftermarket camshaft, PRC 265 heads, stock fuel pump with KB bap, 1000cc injectors running e85. We didn't get a full tune done because of the fuel pressure dropping off starting at 4000 rpm. The tuner said he was only running 2 degrees total timing on the pull and peaked at 8.1 psi. The fuel pressure drop had me freaked out and I was caught off guard that it was making that much boost and I don't want to push the limits of my stock bottom end. What would be a good fuel system upgrade to make sure I have the fuel pressure when I need it? and should I swap a larger pulley or keep it the same? This is with no restrictor plate also, I forgot it at home so I couldn't make a comparison run with it in. Thanks for the replies.

Unreal

Why no restrictor plate? Stock pump will be maxed out around that power on e85. No restictor plate I would full expect 10+psi. A 3.8 pulley typically makes ~7psi and ECS runs a 3.25 on their kits if I recall correctly then restricts it down. That is a 10+psi pulley easy.

Drewstein

Who does dyno pulls from 1500rpm? Also the 2* of timing must be incorrect as that's way too low. Maybe he said he could only add 2*?

Your fuel pressure does fall off a little so I believe you are in need of a pump. There's a few good choices you can go with to fix that issue.

A/F is too lean for my blood.

I would like to see your FP inverted where it starts in the 58psi range and is boost referenced from there. What regulator are you running?

Unreal

Sounds like he is stock, as he wouldn't have a regulator with the stock pump besides the intank one that limits FP to 58psi.

Figure stock pump with a BAP is pushing it at ~700rwhp on pump. Take away 30% for e85 and your out of pump around 500rwhp on e85. Which makes sense according to the graph, once you hit ~500rwhp FP starts dropping.

Drewstein

Makes perfect sense Nick. Just verifying his mods etc of course.

travis1746

it was my fault I didn't have the restrictor, I left it on my tool box at home on accident. Thanks for the responses, I thought I had done my homework on this build but I still have a lot more to learn.

DOUG @ ECS

With E85 your going to need more fuel for our system without the restrictor plate. I would suggest adding our stg 1 system for a fast-easy and clean way to get the extra fuel you need.

Feel free to call or PM me if you have any other questions.

Streetk14

For what it's worth, I'm right near the limits of the stock Z06 pump with a BAP and meth. That's on pump gas around 700 whp. I'd take Doug's advice on the stage 1 fuel system. That's the route I'd go if I ever wanted to push it further.

I'd also be really careful with that AFR. Not trying to discredit your tuner, but it's pretty lean throughout the entire pull. No good on a stock bottom end LS7.

winters97gt

Out if the 3 tuners I've used, I have to agree. All of them would have got out of the run.

I'd consult with ECS, and get a real fuel system. I'm fortunate that my trusted tuner is only 30 miles away, but I'd have no problem driving 300-500 miles for a good tune. Been there, done that.