New HG's installed. Knock over 22psi?

[VxTurboxV]

Recently installed new HG's. Previously I ran 25-28lbs of boost at 22-25* timing. Managed my best ET with 25lbs @ 25* total timing. alky injection on 91 octane 1m15 nozzle.

My heads were webber irons and I had the machine shop remove the o-ring installed on the head and resurface the o-ring grooves out of the head. They cut it down .015. Installed a RJC steel HG kit. .033 compressed thickness. (old gasket was .039). So I'm working with a bit more compression. Factory short block bored .030 TRW pistons.

Car seems to run well enough. I have the boost set at 20psi and it creeps to 22 or so by 5500. Total timing is 21*. (have a powerglide transmission so chip doesn't pull timing in high gear)

If I turn the boost up to 25 my knock sensor sounds.(caspers audible sensor) I let off quickly and the scan master shows no KR. So got back into it a little longer, audible sensor sounds first, then I could hear a slight popping out the exhaust sounding almost like ign breakup and could feel a slight hesitation and then the scan master registered a .9 KR.

Jumped off the gas again. Lowered the boost back to 20 and it runs clean through the whole pass. (creeps to 22)

I usually shoot for mid 11 AFR's @ WOT. I tried upping the fuel to mid 10s and even richer and it changed nothing.

And just to add to the confusion. When I pulled the heads I installed a power glide trans as well. I'm assuming this combined with the 2.73 gears is putting quite a bit more load on the motor. To give U an idea I can foot brake over 20lbs?

I had the car out at the track last weekend, but was fighting a nasty ign breakup at anything over 17-18lbs. Ran a best of 11.01 @ 126. 1.67 60' leaving at 20lbs on the foot brake. Pretty piggish out of the hole for 20lb launch!

Think I should throw the 3.08's back in the rear to ease up some of the stress on the motor?

Thanks!

[scott wile]

Like the convertor? I'd try some race gas just to eliminate the possibilty of detonation and then check to make sure nothing else is rattling that might set off your sensor. I was never a big fan of those things. I'd put the 3.08's (or even 3.42's) in to get the 60' back. The 1.76 low gear of the PG combined with the 2.73 final ratio is not ideal.

[VxTurboxV]

Originally Posted by scott wile

Like the convertor? I'd try some race gas just to eliminate the possibilty of detonation and then check to make sure nothing else is rattling that might set off your sensor. I was never a big fan of those things. I'd put the 3.08's (or even 3.42's) in to get the 60' back. The 1.76 low gear of the PG combined with the 2.73 final ratio is not ideal.

Well honestly it's kinda hard to say scott. Street driving feels quite a bit looser down low than my other stalls, but I think thats just the glide and huge gear.

It seems my big end mph is roughly the same. Possibly a bit better on the big end. since I was at lower boost levels. 1/8th mph slowed down to 99mph. Previously it was around 102-103. Honestly I don't think I've got the power for the current setup....


I'm on a 28" tire currently. I can drop that down to a 27 or 26 to help me out some. The 2.73's are pretty nice for street driving, I'd hate to loose the nice cruise rpm's. If the tires don't help enough. I've still got the 3.08's I could try. I hear that tractor fluid tightens up converters a few hundred rpm as well. May give that a whirl.

Once I've got all the bugs worked out if it's still slipping to much I may need to pull that converter this winter and get it tightened up a bit! No biggie. Still a great deal!

Wish I paid more attention to my RPMS at the end of the 1/4. I was playing with the gearing calc. Seems with a 20% slip figured in I'd be around 130mph @5500 with the current gearing and 27" tire? What kind of slip were you getting scott?



thanks!

[Yullose]

I think a 3.23-3.42 gear would be ideal for your combo... Especially with a 28" tire.

The 'glide has a tall 1st gear... and really needs a better ratio in the rear than 2.73's.

Pick a MPH and RPM you want to see at 1320ft... and gear it accordingly.
The other option is to go back to a 3spd, so you have a lower 1st gear that will work better with tall rear gears.

What feels good on the interstate, isn't 'gonna work good on the track.

My car should go 140mph with 28" tires and a 3.42 gear @ 6200rpm... I plan to drop down to a 3.23 gear so I have "room to grow."

[VxTurboxV]

Thats the plan, I need to figure in the slippage to plan for the gearing though.

[Yullose]

Originally Posted by VxTurboxV

Thats the plan, I need to figure in the slippage to plan for the gearing though.

Have you spoken to Dusty Bradford at all ?

He's a dealer for PTC converters... and really has these turbo cars figured out... I just got mine this week. Maybe he can point you in the right direction ?

[scott wile]

It will stall less with the lower gear ratio(3.42) I was in the 16% range at 6800rpm and 129mph in the 1/8mi. The higher the rpm the more it will couple.

[VxTurboxV]

Originally Posted by scott wile

It will stall less with the lower gear ratio(3.42) I was in the 16% range at 6800rpm and 129mph in the 1/8mi. The higher the rpm the more it will couple.

I've got the 100lb valve springs I believe but I'm running the 212/214 edelbrock cam. So I've been using 5500 as my redline/shift points. So I could probably drag it out to 6k in high gear. I doubt I'll be making much power up there with my current cam though.

Looks like with 3.42's and a 26: tire I'd be 124 MPH calculating in no slippage. So I don't think that will work

I think the converter is the hardest part of my combo to match. I'm guessing I probably slip more than most because of my low redline. So i'd probably need a really tight converter.

I have 3.08, 3.27, 3.55, 3.73's in the attic. Assuming I'm sending the converter out to be matched to my combo which gear sets would U all go with out of the above?

[Budd]

I may be wrong - but I always thought slippage was more relevant to rpm's at a given mph - not subtracting mph. So if at a locked converter rpm/gear/tire size is 5000 rpm at 125 - with 16% you would be at 5K rpm*1.16 with the same mph (5800 rpm).

[VxTurboxV]

Originally Posted by Budd

I may be wrong - but I always thought slippage was more relevant to rpm's at a given mph - not subtracting mph. So if at a locked converter rpm/gear/tire size is 5000 rpm at 125 - with 16% you would be at 5K rpm*1.16 with the same mph (5800 rpm).

That would make alot more sense. Thanks...

[VxTurboxV]

Originally Posted by scott wile

It will stall less with the lower gear ratio(3.42) I was in the 16% range at 6800rpm and 129mph in the 1/8mi. The higher the rpm the more it will couple.

16%? Do you mean 6? Was told by marty at chance racing converters that a high buck converter will run 2-3% at most. A generic style converter that is close to being right for the combo should be be in the 5-7% range?

Is this just not the case with TB's?

[Yullose]

I really think you should talk to Dusty Bradford... He's got a $hitload of his PTC converters in some really fast cars. He has these turbo cars figured out...

I'm not sure if he gets on this site or not, but he's always on the yellow board.

As far as gear ratio goes... I'd probably go with the 3.27's because you have a light car and short tires.

[scott wile]

[QUOTE=VxTurboxV;776332]16%? Do you mean 6? Was told by marty at chance racing converters that a high buck converter will run 2-3% at most. A generic style converter that is close to being right for the combo should be be in the 5-7% range?

Is this just not the case with TB's?[/QUOTE/]
16% in the 1/8th was my statement. Marty Chance is talking 1/4mi %'s. 1/4mi % #'s are always lower. BTW. the last bolt-together $2200 Chance converter I installed was very dissapointing.

[87bigcut]

I vote for keeping the glide in, getting a converter from Dusty at PTC, and add a bit or gear to the rear when you get a chance. Still think powerglide's in turbo cars is a great way to go, and I will be further testing this theory with the new setup this summer.

Joe

[VxTurboxV]

Originally Posted by 87bigcut

I vote for keeping the glide in, getting a converter from Dusty at PTC, and add a bit or gear to the rear when you get a chance. Still think powerglide's in turbo cars is a great way to go, and I will be further testing this theory with the new setup this summer.

Joe

Thanks for clarifying that scott! I was figuring in 16% for the quarter.

I have talked to Dusty. He was very helpful. He suggested trying the 3.27's as well. I can always step up to a 27-28" tire if I need a little more mph. Was also told running some John Deere HyGaurd tractor fluid will tighten up a converter a few 100 rpm or so.

I won't give up on the glide or the converter this early!

I'm swapping in the 3.27's tomorrow morning. Currently running a 26" tire, we'll see how it goes. Unfortunately the track is closed for the year here anyway.

If I'm still getting detonation, I may be converting to e85 this winter.