Thread: KR on stock pully with Flow mods

Hi All,

Today installed a ZZP 3 inch downpipe, an open cone filter attached to the end of the stock intake tubing (where it meets the stock box), Poly mounts, shorter dog bones, and ive already been running autolite 104s. I have a 180* tstat but haven't installed it yet.

I just did some pulls with the stock pulley and I am seeing an average of 3.5* of KR Via Torque with a peak of 5 at the top of 3rd (not shifting). Any ideas what could be causing it? I pretty much expected to be Knock free with these mods on a stock pulley.

is there anything i can monitor via torque to troubleshoot?

My first thought is a clogged fuel filter.

I also just did an engine flush with Motuls engine flush and put in Motul Eco Nergy 5w30, if that matters.

Eh, it happens lol.

Welcome to the 3800 weirdness. Some cars won't knock, others will.

You may have reduced part of the restriction but you can't change the timing and commanded AFR fuel ratio doing what you did. The 104's are overkill for a stock pulley/downpipe combo. The thermostat will mean nothing, it won't help or hurt anything changing it.

On some engines the fueling is too rich, causing knock. Stock calibrations run 10.7-11.0 AFR with ease, which could cause some knock if it's too much. Or the timing needs to be backed off a degree or two to stop the knock. It's a game to play if you had a tuner. You could try 11.5-11.7 AFR, using a wideband to hit that target and or taking away timing or adding timing to see what changes.

Possible that when warmer temps come around that the knock lessens because the air charge won't be as cool thus creating less boost.

Originally Posted by Fivefingerdeathpunch

Eh, it happens lol.

Welcome to the 3800 weirdness. Some cars won't knock, others will.

You may have reduced part of the restriction but you can't change the timing and commanded AFR fuel ratio doing what you did. The 104's are overkill for a stock pulley/downpipe combo. The thermostat will mean nothing, it won't help or hurt anything changing it.

On some engines the fueling is too rich, causing knock. Stock calibrations run 10.7-11.0 AFR with ease, which could cause some knock if it's too much. Or the timing needs to be backed off a degree or two to stop the knock. It's a game to play if you had a tuner. You could try 11.5-11.7 AFR, using a wideband to hit that target and or taking away timing or adding timing to see what changes.

Possible that when warmer temps come around that the knock lessens because the air charge won't be as cool thus creating less boost.

The reason i have the plugs, is because i plan to drop to a 3.5. I already have the pully. I am just waiting for the Puller to arrive tomorrow.

I was checking the knock last night to make sure I had gotten rid of the stock knock before slapping a smaller pulley on. I guess i cant do that now.

It was also about 70* when i did the pull last night.

your gonna need a tune. what rpm does the kr start? and does it keep building or is it a spike at the shift?

Originally Posted by Scottydoggs

your gonna need a tune. what rpm does the kr start? and does it keep building or is it a spike at the shift?

It started around 3500 IIRC. I drove it again today, same temps and off and on rain, and saw a max of 2* . All of the figures are non shift KR.

Just a theory, but I did spill some oil on the manifold when chaning could the smoke have impacted it? Could the computer be adjusting fuel trims with the new DP?

Also, would a can tune deal with this?

how much kr did it show? start small and climb with the rpm's? and this in second gear more so then first?

Originally Posted by Scottydoggs

how much kr did it show? start small and climb with the rpm's? and this in second gear more so then first?

today it peaked at 2*, it started off at 0 and started higher in the rev range and climbed as it approached redline. Im not sure about 2nd vs first but 3rd makes more than 2nd.

2º aint horrible on a stock set up still. was it higher before the dp install? boost drop any?

headers dropped my psi to like 5 from 8, stock pulley. then i did a 3.4 and mad 12 psi. needed a tune at that point lol

I think i was seeing 3 before. The 5 last night scared me, but so far it hasnt been back. I'll probably put the 3.5 on on tuesday, see what happens. Worst case, ill get a can tune from ZZP. I have 2 other cars, so i can live without the Buick for a bit.

have you scanned the o2 sensor yet? wot it should be hitting 930 ish (mv) and stay there. if its drops that can cause kr. i had one drop to 0.78. chased my tail for a bit on that one.

Originally Posted by Scottydoggs

have you scanned the o2 sensor yet? wot it should be hitting 930 ish (mv) and stay there. if its drops that can cause kr. i had one drop to 0.78. chased my tail for a bit on that one.

I havent.

Until i did mods, i figured the 3* stock was pretty normal so I didnt pursue it at all.

I did do a pull before the car hit 180* at about 150, i had 0 KR.

Originally Posted by SgtMarshal

it doesn't make sense to me to put a smaller pulley on when you already have kr on the one you have.

I agree, but at the same time, I'm borrowing the puller from Scotty, and i can afford to park the car until i sort everything out. Certainly not ideal but forces me to sort it out.

just stay out of boost untill you figure it out.

it's what I've been doing untill I sort out my crap.

boring? yes. better then popping a piston? yes

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I'm going to try and scan the o2 tonight using torque. If i dont see anything out of the ordinary, im going to send my ECU to ZZP, and have them flash it.

Originally Posted by SgtMarshal

are you on facebook? there is a guy I had tune my car on there. top notch customer service and great tune.

Zeph Hattan | Facebook

I am not, I'm mainly going with ZZP because of the store credit I have. Should be able to get the PCM for about 25 bucks.
I checked the o2 sensor and it stayed at 1 volt (probably torque rounding) at WOT.