Since I am no longer misfiring, I went to the dyno the other night. After some steady-state tuning, we made a few pulls. I started out with 5 psi, and worked up to 6.5 psi when I ran out of fuel capacity. Increasing VE didn't result in lower AFRs, so I ordered a new pump and filter.

The parts:

stock 130k mile 1.6, Saab T3, starion IC, 550s, diy log manifold, 2" charge piping, 2.5" full exhaust, MS fuel, spark, and boost control

I ended up with 145 hp @ 6500, 127 tq @ 5500.

I was hoping for a bit more, but not being able to up the boost due to fuel held me back. I'll add a new Walbro, maybe a Knocksense and try it again.

Thoughs?

 

you're not asking much from your pump, at the base pressure...but hopefully that's the ticket and it's just on it's last breathe.

fwiw, your VE numbers look really high.

not bad numbers on a mustang though, but the peak HP would have been higher if you keep it in to 7000RPM.

 

need BIG pictures

 

The pump is of unknown age, so who knows. I figure it is cheap insurance. On the other hand, if it doesn't fix the problem...?

That is intentional. I got the idea reading the msefi forums. With larger VE numbers in the table, each VE% change results in a smaller change in fueling. For example, if your idle VE was 10, the smallest unit you could adjust it by is 10%. If that same VE is 40, the smallest unit is 2.5%. The original poster actually recomended scaling your Rec Fuel so your largest VE was near 255, giving you the largest tuning resolution. At least that's what I got from it. Things seem much smoother now, especially with EGO correction on.

Agreed. The 'no attachments' thing caught me by surprise. Anything specific?

I thought it was interesting that my AFX in the dp read 11:1 rising to 12:1, while the dyno WB read 12:1 all the way across ( the dark line 1/4 way up).

 

wow i would have expected 180 or so with a t3. im sure your exhaust could be a little larger.

oh nvm thought you were running higher boost. not too bad man.

 

It's easy enough to check the capacity of your fuel pump... just get a gauge and test it. How about a new fuel filter as well?

Don't Mustang Dyno's also report about 10% lower than others... maybe add 10% for what we're used to seeing on a DynoJet... and 160whp is pretty good at 6.5psi.

 

I've checked the base pressure, looked fine. I have the maintenance records since it was 20k miles old, it's the original pump. Considering it's age, price of a new one ($85 shipped) and the ease of replacement, it's cheap insurance. I've got a new filter as well, and I might replace the rubber lines also. At 18 yrs old, their probably due.

Up to 20% depending who you talk to, but I think that may be a little optimistic. I'm not super concerned with the number, but it's nice to know I'm in the ballpark.