Curly I don't agree with your pressure analogy at all. I dont see how your engine runs at 45lbs fuel pressure but too each his own.

If you continue to use the exact same starting line methods you can expect much of the exact same results.

CHodge,

A 31/70 with a 0 pump should be really close to the same amount of fuel as the 31/98 with the 1/2 pump. So worth a try.

Traction was just an example. My point was are you sure it isn't one of the 100's of other things that can cause these things to not print tickets. Heck I fought mine for longer than I'd like (started last year) to admit recently... it was deadly then slowly started to move around a little. Finally in was also running off pace by a tenth at times. Against my better judgement I chased the tune (which was known good previously) and other fuel related things and it didn't help at all. Also chased all of the normal electrical things. Long story short i am positive it ended up being the camshaft. 2nd time out this year the cam broke in half. Replaced the cam a bam it's back to printing tickets.

Scott

I’m going to try the 31/70 and lower the timing to 34. The timing was dead center of the bend with 35 degrees and with the 39 the whole strap is hot so I’m sure to much timing. I’m wondering if it could be an intake gasket sucked in causing it. Hopefully the rain will hold off to get 3-4 passes tomorrow and see if the tune change and timing helps. If not maybe we will find something in a few weeks when we tear into it.

I really don’t think it’s a tuneup issue. I think it’s something small but can’t pinpoint it. Looking at the rpm graph on the grid it’s smooth in every run. So I don’t think it’s ignition/fuel or it would show a miss or dip in rpm. Frustrating when the car has been deadly then starts moving .05

quote:

Originally posted by C Hodge:
I really don’t think it’s a tuneup issue. I think it’s something small but can’t pinpoint it. Looking at the rpm graph on the grid it’s smooth in every run. So I don’t think it’s ignition/fuel or it would show a miss or dip in rpm. Frustrating when the car has been deadly then starts moving .05

In Grid Data Acquisition, zero the runs and then do an overlay of the faster to slower to try and determine where and why the difference is possibly happening.

If shifting with Grid, are you using the Shift Light or Output Switch feature to shift with?

I have 8 O2 sensors and if there is a problem with fuel it will show up. Even a partially clogged nozzle still work but the mixture will be off. Mine runs best t 12.9 to 13.1 on the gas scale. If one is clogged partially it will read 14 or 15.

Just remember with MFI the fuel flow and pressure will always follow the engine RPM, so if you have some inconstantcy with your converter/ trans it will effect how much fuel goes in your motor. so try and keep your stage trans temp the same. A hot/loose converter will put more fuel in and a cold/tight converter may put less in both affecting your consistency

Shifting on time through the K&R box.

quote:

Originally posted by C Hodge:
Shifting on time through the K&R box.

Consider trying the Shift Light RPM feature in Grid to shift with.

As I wrote prior, do the Grid overlays. This shows what maximum rpm is achieved after shift completed and at what time this occurred.

I’ll check all the runs later today. Rained out so headed back home

On reading the parts about engine temp, anybody running or recommend running a T stat with MFI? I don't have anything as of now, and it's tough to get engine temp!!! Kinda nice though, with gas and carbs, 3-4 min of idle time and it was 160-180 and hard to keep cool!

quote:

Originally posted by Coloradoracer:
On reading the parts about engine temp, anybody running or recommend running a T stat with MFI? I don't have anything as of now, and it's tough to get engine temp!!! Kinda nice though, with gas and carbs, 3-4 min of idle time and it was 160-180 and hard to keep cool!

I run a Thermostat and I have a fan on thermostat both to help keep engine temps where I want it.

Now on the thermostat I did drill four holes about 1/8 inch in diameter to allow some water to flow all the time and help get air bubbles out when filling. I think the water thermostat is 170* and the fan is set at 180^

quote:

Originally posted by Coloradoracer:
On reading the parts about engine temp, anybody running or recommend running a T stat with MFI? I don't have anything as of now, and it's tough to get engine temp!!!

As SCDIV1 wrote on Page 1 “Pull your fuel shutoff to lean it out and get the temp up before making a run if you don't have a primer plus...”

Your BV might be set fat and could use leaning if loosing temp at idle after you achieve the desired water temp.

quote:

Originally posted by markemark:
As SCDIV1 wrote on Page 1 “Pull your fuel shutoff to lean it out and get the temp up before making a run if you don't have a primer plus...”

Your BV might be set fat and could use leaning if loosing temp at idle after you achieve the desired water temp.

I do that, can get it to about 150, but it doesn't retain heat. I was thinking a t stat would help maintain it.

Didn't mean to derail the thread...