dyno results and A/F ratio

[Kevin - Blown 95 TA]

Yeah, it looks like the fire was trying to blast it's wau thru the poor gasket. Get some that can tolerate the misalignment and get the flanges flattened.

[Craig 94 TA GT]

Thanks for the tips guys. The header flanges aren't too bad. When they were new, I measured the biggest gap to be just under 1/32". With the Percy's stacked aluminum, I'd assume that gap should close up well. When I checked the passenger's side, the biggest gap was 1/16" or so, but BLMs are very close to a perfect 128.

When I'm finished with all the testing, poly mount install and new gaskets, I'll recheck my BLMs...and if the split is gone (as well as the KR), I'll be one happy f-body owner

[fastTa]

Thanks for the tips guys. The header flanges aren't too bad. When they were new, I measured the biggest gap to be just under 1/32". With the Percy's stacked aluminum, I'd assume that gap should close up well. When I checked the passenger's side, the biggest gap was 1/16" or so, but BLMs are very close to a perfect 128.

When I'm finished with all the testing, poly mount install and new gaskets, I'll recheck my BLMs...and if the split is gone (as well as the KR), I'll be one happy f-body owner

Percy's makes some good stuff. I've personally never used their "dead soft" stuff, but everyone says it's good.

[Craig 94 TA GT]

Sweet! I'm looking forward to getting them in tomorrow.

Maybe I'll also get the LS1 MAF sensor, which supposedly replaced the LT1 sensor. It's dirt cheap, on sale at fullthrottlespeed.com. I hope that cures the problem why my 24#ers are running beyond 90% duty cycle on my stock motor.

[Craig 94 TA GT]

Your guys' suspicions are confirmed. I looked at the head and saw black all over that area. Can a leak this close to the head be worse than a leak at the y-pipe?

[Z Ya Later]

Your guys' suspicions are confirmed. I looked at the head and saw black all over that area. Can a leak this close to the head be worse than a leak at the y-pipe?

Well good job lol

I would say so, since you're getting all the fresh air sucked into the header and throwing off the O2 sensor. But that's just an opine of mine lol

[Craig 94 TA GT]

That's what I was thinking too
I'm wondering though, if it's that close to the exhaust valve, does that affect anything other than the O2 reading?

[fastTa]

That's what I was thinking too
I'm wondering though, if it's that close to the exhaust valve, does that affect anything other than the O2 reading?

It could throw off alot of things. Depending on how much eduction was actually taking place, it could have been messing with the amount of a/f being drawn into the cylinder during overlap. You could have also had some reversion and it could have been prematurely cooling the exhaust valve.

[Joe 1320]

It could throw off alot of things. Depending on how much eduction was actually taking place, it could have been messing with the amount of a/f being drawn into the cylinder during overlap. You could have also had some reversion and it could have been prematurely cooling the exhaust valve.

Yep. What he said.

[fastTa]

Yep. What he said.

I'm no expert, but I do what I can to get by!

[Craig 94 TA GT]

How about a leak from cylinder to cylinder? Any ill effects? The passenger's side had one. I didn't notice anything odd with that side's BLMs though.

BTW, the Percy's look awesome. Uncrushed, it's as thick as 2 Felpros.

[fastTa]

How about a leak from cylinder to cylinder? Any ill effects? The passenger's side had one. I didn't notice anything odd with that side's BLMs though.

BTW, the Percy's look awesome. Uncrushed, it's as thick as 2 Felpros.

Well, the exhaust valve would be closed on the adjacent exhaust ports the entire time except the upper part of the exhaust stroke on those respective and adjacent exhaust ports, which also coincidentally would be different from that of the leaking exhaust port. So it is highly doubtful that a leaking header gasket on one cylinder, would have a directly adverse affect on an adjacent cyinder.

Just brainstorming here(brain-farting actually), but I suppose if you were to have enough turbulence generated by that one leaking primary, it could create a slight interference with the normal continuance of exhaust gas velocity further down-stream. I wouldn't think this specifically would have much of an effect on the amount of oxygen that the o2 reports seeing, but it could, I suppose, have an adverse affect on performance. Brain fart over.

[Kevin - Blown 95 TA]

That piddly amount leaking thru the header gasket wouldn't do nuthin, but it's not helping either. Gaskets have made great leaps & bounds these days, and I just use the best I can get for this LT1 and these kinds of problems are a thing of the past. Use the Percys or the Earls and some kind of good fastener and quit worrying about header leaks.

[Craig 94 TA GT]

Thanks guys. I think the other side of the passenger's side gasket looks a bit messy http://s94938520.onlinehome.us/pictures/pass_side2.jpg but again, if there's no 'out of whack' O2 readings, I guess it was ok.

I'm looking forward to putting on these:


I'm also in the middle of the poly motor mount install. Biggest PITA I can imagine. If only I would've done it during the header install

[Joe 1320]

Now you can see why I recommend them. Make sure you install the convex (smooth) side toward the block.

You can modify the gaskets to allow the end two bolts to be "slip over" by notching out the bottom half of both end bolt holes. This will allow you to remove all the header bolts except one on either end, allowing the header to still stay in place, the gasket is slipped in between the header and the block.... settling right down over the bolt on each end. Then you simply install the rest of the header bolts and torque.