Thanks BigBird!

[enkeivette]

http://i160.photobucket.com/albums/t196/big2bird/MSDbushings.jpg

BigBird made some custom bushings for my distributor (6, 8 & 10 degrees), now I can run 18 initial and limit it to 24 total.

If you want to have your dist setup properly, you know who to call, and it ain't ghost busters. :hail:

Will report back after tuning tomorrow.

[SeanPlunk]

Very slick! Keep us updated.

[94cobra69ss396]

http://i160.photobucket.com/albums/t196/big2bird/MSDbushings.jpg

BigBird made some custom bushings for my distributor (6, 8 & 10 degrees), now I can run 18 initial and limit it to 24 total.

If you want to have your dist setup properly, you know who to call, and it ain't ghost busters. :hail:

Will report back after tuning tomorrow.

Good to hear but I still think you are running too much timing for 10psi of boost. You still need to add a boost retard so that you can get the most out of that engine without it pinging in the higher boost levels.

[big2bird]

http://i160.photobucket.com/albums/t196/big2bird/MSDbushings.jpg

BigBird made some custom bushings for my distributor (6, 8 & 10 degrees), now I can run 18 initial and limit it to 24 total.

If you want to have your dist setup properly, you know who to call, and it ain't ghost busters. :hail:

Will report back after tuning tomorrow.

Use only stock plugs, no exotics. They missfire under extreme pressures.
Use .035" gap or smaller. The more cylinder pressure, the smaller gap required.
Set the initial to 16* with a timing light to start, with wires unplugged. Start the engine, and set the high end to 24*, then bring it to idle and see where you are. If it kicks at restart, change bushing to 8* and reset.
As you determine the best idle timing, and the high end of advance you can go, we can make a final bushing if you need one.:thumbs_up:

[big2bird]

Good to hear but I still think you are running too much timing for 10psi of boost. You still need to add a boost retard so that you can get the most out of that engine without it pinging in the higher boost levels.

While that would certainly make it easier, I feel that adding an intercooler would yield more benefits. Of course, it will be a nightmare. I can see 4 hood pins with no hinge, sugar scoop headlights to give him more room, and lots of fittings and obstacles to install it. In a C-3 with no cooler, his boost air must be really hot, and is not helping at all.
I would also like to see less boost, and more alternator rpms to lower his idle speed.

[enkeivette]

An intercooler is on my future. A long thin one will nestle where my frame extension used to be. I can fit a 9"x30" or at an angle, more like a 12"x30" no hood mods necessary.

Will not turn down the boost. And from 34 to 24, I think the timing should be fine now.

[Vettezuki]

. . and more alternator rpms to lower his idle speed.

Please explain. I don't understand.

[94cobra69ss396]

While that would certainly make it easier, I feel that adding an intercooler would yield more benefits. Of course, it will be a nightmare. I can see 4 hood pins with no hinge, sugar scoop headlights to give him more room, and lots of fittings and obstacles to install it. In a C-3 with no cooler, his boost air must be really hot, and is not helping at all.
I would also like to see less boost, and more alternator rpms to lower his idle speed.

That's my piont. I'm also running the Cobra without an intercooler and I only have 17* total timing although I now have 11-12psi. If I bump it up so that I have 21* I get detonation. I think if he's going to run it without an intercooler that he should back the timing down to be safe. Sure it will have less power on the top end but at least he won't break another piston. He obviously can't hear it detonating even though it was. Then when he takes it to the track he can run it on race fuel and add more timing.

I guess I'm just overly concerned because I can hear mine detonate if I have too much timing. I've actually back the Cobra down to 15* total for summer because when I have the whole family in the car and run the air it will ping a little in the upper rpms if I get on it on hotter days.

[big2bird]

Please explain. I don't understand.

His alternator is running too slow, and he is dropping ignition below 1,000 RPM.

[big2bird]

That's my piont. I'm also running the Cobra without an intercooler and I only have 17* total timing although I now have 11-12psi. If I bump it up so that I have 21* I get detonation. I think if he's going to run it without an intercooler that he should back the timing down to be safe. Sure it will have less power on the top end but at least he won't break another piston. He obviously can't hear it detonating even though it was. Then when he takes it to the track he can run it on race fuel and add more timing.

I guess I'm just overly concerned because I can hear mine detonate if I have too much timing. I've actually back the Cobra down to 15* total for summer because when I have the whole family in the car and run the air it will ping a little in the upper rpms if I get on it on hotter days.

Thanks. Now I understand your concern. Hmmmmmmmmmm

[Vettezuki]

His alternator is running too slow, and he is dropping ignition below 1,000 RPM.

What's the cause? Does he have an underpulley?

[94cobra69ss396]

His alternator is running too slow, and he is dropping ignition below 1,000 RPM.

With the cam he has and the fact that he is driving the supercharger I don't think it will idle below 1000rpms anyway. The cam in the Cobra has 220* at .050 on a 110 LSA and it idles at 1000. The Chevelle also idles at 1000 with 246* at .050 on a 110 LSA but it's not driving a supercharger. The supercharger take a lot to drive even at an idle.

What is the voltage output from the alternator at 1000 and below?

[big2bird]

What's the cause? Does he have an underpulley?

Yes

[big2bird]

With the cam he has and the fact that he is driving the supercharger I don't think it will idle below 1000rpms anyway. The cam in the Cobra has 220* at .050 on a 110 LSA and it idles at 1000. The Chevelle also idles at 1000 with 246* at .050 on a 110 LSA but it's not driving a supercharger. The supercharger take a lot to drive even at an idle.

What is the voltage output from the alternator at 1000 and below?

I haven't looked at the car. This is heresay from a casual conversation last night.

[enkeivette]

Motor will idle lower than 800, but below 1K (or 900, found out today) it will not charge and it will drain the battery in a few mintues of idling. The crank pulley and alt. pulley are custom offset units from ATI (Procharger), can't change them without giving up the blower.

CobraSS, as I'm sure you know comparing your Chevelle to your Mustang, different motors take different timing. I'm back 12 degrees from stock, what does a stock Cobra want to see?

[enkeivette]

Bird, sorry I didn't get back to you. I was out... late. Earlier today I changed out the pump cam, turns out I had a green one installed already (totally forgot). Installed my blue one which is a little more aggressive. Helped the off idle lean spit, but not in the mid rpms. When the vacuum guage tips close to zero the carb still spits. Going to up the jet sizes from 67s to 69s tomorrow and see if I can correct the spit without going much below stoich at cruise.

If that doesn't work I'm busting out the drill and attacking my PCVRs.

The alternator works great. Helps it idle more consistently and at a lower rpm with the advanced base timing. Turned the motor off at 3K and fired it back up like you suggested, no problem.

[94cobra69ss396]

CobraSS, as I'm sure you know comparing your Chevelle to your Mustang, different motors take different timing. I'm back 12 degrees from stock, what does a stock Cobra want to see?

36* just like a SBC or BBC.

[94cobra69ss396]

Bird, sorry I didn't get back to you. I was out... late. Earlier today I changed out the pump cam, turns out I had a green one installed already (totally forgot). Installed my blue one which is a little more aggressive. Helped the off idle lean spit, but not in the mid rpms. When the vacuum guage tips close to zero the carb still spits. Going to up the jet sizes from 67s to 69s tomorrow and see if I can correct the spit without going much below stoich at cruise.

If that doesn't work I'm busting out the drill and attacking my PCVRs.

The alternator works great. Helps it idle more consistently and at a lower rpm with the advanced base timing. Turned the motor off at 3K and fired it back up like you suggested, no problem.

What did you do to the alternator?

[enkeivette]

Haha, oops, typo. I meant to say the distributor works great.

Didn't get a chance to tune today. Worked on the gf's car. 1.6L of fury.

I did notice while I was driving that the lean stumble actually starts as soon as 5" of vacuum. I've been thinking about reinstalling the 6.5PV. If it opens sooner it might make up the difference to keep the AFR happy. What do you guys think? Now that I have more timing and a higher idle, vacuum is closer to 8".

[BRUTAL64]

Haha, oops, typo. I meant to say the distributor works great.

Didn't get a chance to tune today. Worked on the gf's car. 1.6L of fury.

I did notice while I was driving that the lean stumble actually starts as soon as 5" of vacuum. I've been thinking about reinstalling the 6.5PV. If it opens sooner it might make up the difference to keep the AFR happy. What do you guys think? Now that I have more timing and a higher idle, vacuum is closer to 8".

What's your vacuum at idle?

[big2bird]

What's your vacuum at idle?

Well, since I'm idle all week, some would say I live in a vacuum. Of course, if the time /space continuim doesn't tear.:huh:

[BRUTAL64]

Well, since I'm idle all week, some would say I live in a vacuum. Of course, if the time /space continuim doesn't tear.:huh:

:smack::smack::smack::smack:

[enkeivette]

What's your vacuum at idle?

Now that I have more timing and a higher idle, vacuum is closer to 8".

:truestory:

[BRUTAL64]

"Now that I have more timing and a higher idle, vacuum is closer to 8".

Ok, don't remember seeing that. 6.4 PV should be fine.

[enkeivette]

Update:

Installed the 6.5PV, doesn't lean spit at low rpm, only mid rpm.

Installed the 69 jets on the primary block. Didn't do much, drives a liiitle better.

Leaned out the idle mixture screws, discovered something! The idle mixture screws have a big effect on cruise AFR. So before I drill out the PVCRs, which I almost did today, I'm going to richen the main jets while leaning the idle mixture to see if I can get it rich enough not to spit without dropping below a 14.5 cruise AFR.

I can see the light, and hopefully I can leave my drill in the droor.

[big2bird]

Leaned out the idle mixture screws, discovered something! The idle mixture screws have a big effect on cruise AFR.

http://vettemod.com/forum/showpost.php?p=50343&postcount=32

[Vettezuki]

http://vettemod.com/forum/showpost.php?p=50343&postcount=32

That was an awesome post. I think I might have actually understood and learned something.

[enkeivette]

Good read Bird, thanks!

Not happy yet, but definitely getting somewhere. Changed the 69s to 73s and the secondaries are still 80. I would have liked to have tried 71 but 73 was the next size up in my collection.

http://i29.tinypic.com/23vahqt.jpg

The idle AFR is pissing me off, I'll tune it to 14.7:1 and all is fine, let the car sit for 20 mins and it wants to idle at 17:1. :rant:

So I have it sort of stable now at 14.7 again with a cruise in the high 13s and under boost she is in the low 13s. I could leave it as is, but I'd like to lean out the cruise a bit more and get it around 12 under boost. Still haven't gone WOT, don't want to till I get it around 12 under boost.

There is no longer a lean spit btw.

I'm thinking about buying and installing 71s and 84s. What do yall think?

[big2bird]

I sent Lars a link to VM. He is the carb guru.

[big2bird]

I sent Lars a link to VM. He is the carb guru.
http://vettemod.com/forum/showpost.php?p=50502&postcount=6
The defenitive answer. Far different from what I expected, but Lars is the guru.:thumbs_up:

[Vettezuki]

Invalid Post specified. :huh:

[big2bird]

Invalid Post specified. :huh:

Try again.:D

[Vettezuki]

Try again.:D

Got it. Lars is smart. enkei, I think you'd be wise to follow his guidance.

[enkeivette]

Got it. Lars is smart. enkei, I think you'd be wise to follow his guidance.

Lars wants me to put back in the stock HSABs with smaller jets than I ran when I had a 15:1+ WOT. Uhhh... no. I like my pistons now, all in one piece, think I'll keep them that way.

I pulled off a 12:1 AFR under boost with the 28 HSABs, I'm at 13.5:1 now. I'm going to increase the jet size close to Lars recommendation while keeping the 28 HSABs and keep going up until I hit 12:1 again.

As Lars recommended, I'm going to install smaller IABs (74s) and retune the idle mixture screws for 14.7:1 and hopefully my cruise and idle will be spot on. It's not that bad right now.

Realistically, I'm really close. I would probably be fine driving the car daily and taking it to the track as is. 13:1 ain't gonna hurt anything with only 24 degrees of advance. Your 12:1 compression Torco motor is around 14:1+ AFR at WOT.