Richard@WCCH

iTrader: (3)

Thanks for the input Colonel. A converter is in the works. Probably 2500 stall. I actually love the way my car runs right now, it's just that I'm trying to eliminate some light throttle KR and I believe that the stock manifolds and Y pipe are a major cause. I've fiddled with timing to no avail. I don't think that the shorty headers will get the job done, therefore my search for small dia. LTs. On the other hand, the Kalifornia smog ***** will likely be a problem with the LTs.......decisions, decisions.........

Richard

MyLS1Hauls

iTrader: (2)

No need to be an ******* Guys like you huh? Thats sounds just a little arrogant. Just because something should work a certain way, doesn't mean that it does. I never said it was the Bible and have never treated mag. results like that...just said that those were there results and its something to think about. BTW, West Coast Cylinder Heads doesnt make money selling cylinder heads to guys like me.

Colonel

"it's just that I'm trying to eliminate some light throttle KR and I believe that the stock manifolds and Y pipe are a major cause."

You can eliminate the KR with the stock manifold. Here are a few thoughts...

The stock Y-pipe has a bad rep based on it's appearance. There is nothing wrong with it. It flows just as well as a round pipe of equal inside diameter. This has been dyno proven a few times through the years.

Cats cause ALOT of KR. Unfortunately, in California you gotta have 'em. If high flow cats would be legal for you, I'd get them. They might help with the KR and they certainly would free up a little power.

Do you know for sure that your KR is real and not false? Autotapping with some unleaded race fuel in the tank would tell the tale. If it cures the KR, then the KR is real and the problem should be addressed. If it doesn't, then the KR is false and you should find out what's causing it (exhaust hitting something, wobbly crank pully, etc...) or you could have the sensitivity of the KR sensors programmed down.

Colonel

BTW, a 2500 stall will drive pretty much like a stock converter, which may be what you want. While you will see a noticable gain, you'll be leaving ALOT of performance on the table compared to higher stalling converters, but you'll hardly know the converter is there in daily driving.

Richard@WCCH

iTrader: (3)

MyLS1Hauls: While I appreciate your point about what Hotrod magazine thinks I should do, I have a pretty good idea of what I'm looking for, hence the title of this post. My intent was not to stimulate debate about weather I'm and "*******" or to sell you anything much less cylinder heads.

Peace.


Colonel: The KR is is almost always present at light TPS. It appears on my Tech2 as well as Scan Ease. It's even audible now that we're in the heat of summer and I'm driving with the ac on. I've run the car with 100+unleaded fuel and still see and hear some light KR. I've slashed timing in the affected load cells and while it's helped a bit, it hasen't eliminated the problem. Some stall in the converter will help KR a by deferring load to a higher rpm where the load is less. I've driven cars with higher stall converters (3200rpm) and wasn't impressed with daily driveability. Too much slip for my liking. It's looking like 2400-2600rpm stall will be a happy medium. I'm not looking for serious drag race performance, but am trying to find a balance between daily driving and KR reduction.

My intent is to install highflow cats along with headers. I've studied a variety of headers for fit and performance and have not been comfortable with any of the long tubes except for FLP's system. Ground clearance is important since I have to deal with speed bumps and driveways.

It appears that 1 5/8" long tubes are wholly unpopular and so I'll look for some other alternative.

Richard

Colonel

Richard, with 100% unleaded 100 motor octane racing fuel in the tank, there is practically no way that you're actually getting detonation unless you're running running an extremely high compression ratio. I don't know what you're hearing but with 100 octane fuel it most certainly should NOT be detonation...especially with the timing advance knocked back. If what you're telling me is correct, you shouldn't expect to correct this problem with headers or a looser converter.

Just to make absolutely sure that this KR is indeed false (and I'm about 99% convinced that it is based on what you've said), try this...

NEW TR-6 plugs. Worn plugs will cause hot spots and pre-ignition.
A 160 degree thermostat with cooler fan settings.
Run the tank dry and then put in a few gallons of at least 98 octane (I mean MOTOR octane. NOT research or R+M/2 octane.)
Be sure you have no diagnostic trouble codes.

If you still have KR, check your exhaust system to ensure that NO contact is being made with ANYthing else at ANY point under any circumstance (as in, when the engine torques over under acceleration.)

Richard@WCCH

iTrader: (3)

With the exception of adding 100 octane fuel, I've already done all the things you mentioned. Compressin ratio is 10.75:1. The cam is 220º .581" 112ºlsa +4º. The exhaust system is an oem SLP dual, dual setup. When I switched the intake manifold to an LS6 non EGR I completely remapped the high octane timing table. Driving in stop and go traffic with the ac on in the heat there is audible kr and it shows up on the Tech 2 with as much as 8º-10º kr. In cooler weather with the ac off I get very little kr. The dealer replaced the CATS recently, but it didn't change the problem.
I guess the next step is to change converter and change the cam. More duration and wider lobe centers should help knock down the cylinder pressure. Adding headers and highflow CATS will virtually eliminate any kr.......I hope.
Thanks for your suggestions Colonel. I'll try the 100 octane as soon as this tank is dry.

Richard

MyLS1Hauls

iTrader: (2)

Richard,
The narrow LSA keeps low rpm cylinder pressure down, not the other way around. There should be no reason why you can't run that cam. What year is your car? There was a Tech. service bulletin out for this for the 00 cars and it included a PCM reflash. It completely cured my part throttle tip in ping, but that was before I had edit. Did you add timing to the RPM/load where the motor pings? I'd start pulling some timing before I changed out the cam. Also, I'd adjust shift points so the motor isnt lugging...but it depends on where/when its pinging.

Colonel

Richard, your problem is not normal and I honestly think you're trying to bandaid the problem without actually addressing it. There should be absolutely NO problem with running that cam (or even the stock cam) with that compression ratio.

"When I switched the intake manifold to an LS6 non EGR I completely remapped the high octane timing table. Driving in stop and go traffic with the ac on in the heat there is audible kr and it shows up on the Tech 2 with as much as 8º-10º kr."

More and more, I think you have a programming problem. I'd put all of the timing exactly back to stock and start over. If you put it back to stock and still get the part throttle pinging, pull a couple of degrees across the board and try again.

Richard@WCCH

iTrader: (3)

Brad: Thanks for the tip about the pcm reflash. I'll check into it today. I've adjusted all the shift points to keep the engine from lugging. It almost feels like an M6 without the work! I've also changed the rear gear to 3:42 from the factory 3:23.

If I put the timing back to stock I'll have massive kr. My car is a '00 SS SLP level 2 car originally equipped with an EGR. I changed the intake to an LS6 non EGR at the same time that I did the heads and cam install and that's when the kr started. I've compared my high octane timing map to a later non EGR ('02 SS) and found there to be a big difference due to the elimination of the EGR valve. I copied the '02's timing map and it helped a lot but I was still getting kr. I further cut timing in the most affected load cells until the kr was virtually eliminated. Then came the heat and the return of the dreaded kr.

My tank is dry and I'm going to try some 100 octane unleaded today. I'll log a scan on my way home and see if the kr is gone.

I've reviewd a recent scan log and found the LT's go more positive the hotter the ECT climbed. This seems contrary to what should happen as ECT rises. I'll see what heppens with the good gas. Thanks for the input guys.

Richard

Colonel

Ahh, I understand. One more thought. Check for vacuum leaks. That would cause a lean condition especially at lower throttle positions when the incoming unmetered air would make up a greater percentage of the whole. You said it started with the new intake...changing the intake would be a PERFECT time to introduce a vacuum leak.

Keep us up to date. This is an interesting problem.

Fierce-LS1

iTrader: (3)

Hey Richard,
Long time no talk. I'm still gathering up $$$ for the stage 2 H/C. So I will see you before November. This is Zoltan. I am actually running 1 5/8 tri-y headers with a 2.5 inch collector that is just perfect for a daily driver. I put these on with true duals and I gained 3 tenths at LACR. I don't know if you've heard of tri-y headers but is seems to be working for me. They are great for low and midrange torque and provide enough HP up top. I have a bunch of info I gathered about them through research. If you want the articles, let me know. Here are pics of my setup.

http://community.webshots.com/user/fiercels1

Zoltan

Richard@WCCH

iTrader: (3)

Hi Zoltan. How ya doin' pal? I really like your tri-y headers. I'm very familiar with tri-y headers as they were factory installed on my Jensen Healey way back in 1972. They deliver excellent low and mid range performance which is what I'm looking for. Were these custom made for you? They appear to be just what I'm looking for, for my daily driver. I don't want to change the exhaust from the y pipe back because I really like my SLP dual, dual setup. I just want something to reduce the bottleneck out of the heads.
It looks like the tri-y's offer a lot of ground clearance. Another plus. Are those high flow cats you installed?
Nice job on the entire exhaust system. It looks very clean. Thanks for the tip Zoltan, I'd like to learn more about the tri-y's.

Colonel: I appreciate all your suggestions. The problem never changed when late last year I had to pull a head and replace a bent valve. I've replaced the throttle body and the MAF and still the problem hasn't changed. I'm pretty confident there are no vacuum leaks but I've learned to never say never.
I plan on going over all the intake manifold connections this weekend to see if a vacuum leak could be the cause. I'll post more when I have some questions or answers.

Richard

Fierce-LS1

iTrader: (3)

Hey Rich,
I sent you mail !

Richard@WCCH

iTrader: (3)

Update:
Well, I gassed up with some Sonoco 104 octane unleaded and the pinging stopped. The silence was such a sweet sound despite the 100º+ weather and ac on high. That answers some questions and asks more questions. I guess I have some adjustments to fuel and timing to make although some headers and a converter will go along way to fixing my problem. I searched for any possible vacuum leaks but could find nothing. The power with the high octane fuel is impressive despite the high temps.

Thanks much Zoltan.
Stop by and say hi sometime soon.

Richard

Ragtop 99

iTrader: (7)

Back to the original issue.

Coated headers with merge collectors may help your car. The merge collectors should help the low end torque and the coating may help with the heat transfer.

ToplessTexan

Richard, some comments from the C5 camp...

As an FYI TTS's equal length LT design for C5s is 1-5/8". I know it's apples and oranges to compare F-body (single) and Y-body (dual) exhausts, but hey. I've been happy enough with mine that I haven't reached activation energy on what I really want, the high dollar LGM LTs. I've also noticed folks more prone to complaining about loss of torque when switching to larger primaries. Go figure... I don't see a whole lot of used C5 TTS LTs for sale nor do I see lots of complaints about them (other than "they're hard to install" whining.) I know they're out there so maybe there are some folks who are fat, dumb, and happy running 1-5/8" LTs.

Richard@WCCH

iTrader: (3)

Is the fbody header that TTS makes also 1 5/8"?
IMO it's a no brainer to use 1 5/8" LTs to get the best low end torque that a daily driver A4 car needs. Sure the 1 3/4" LTs will make more hp at higher rpms, but the reality is my engine doesn't spend much of it's time at those speeds. The tri-y's that Zoltan mentioned above are also an excellent low and mid range torque header design.
Thanks for your input Topless. It's reassuring to see your results are similar to my expectations despite the different model cars we drive.

Richard

ToplessTexan

No, I believe the F-body header is 1-3/4". It might be worth a chat with Steve Cole to find out why. They might be willing to build a set in 1-5/8" for you, never know until you ask. Vette pricing though...

Tri-Y... Now that's old school Should work well in your app if you can't find a tuned, equal length LT in the smaller diameter.