Edelbrock vs Gen 2 Whipple

[HRSEPLA]

I am just jumping in here late without having a chance to read prior pages but I am assuming 93 octane, have you tried better fuel from a Mobil or a BP?
Sorry if this has been covered already but I battled this early in my build when using Kwik Trip 93. Per Lund, I drained it and moved to Mobil and my knock sensor loved it immediately giving it full timing.
I also used Boostane with great results. This DOES 100% show improvements if octane is your problem. (from my repeatable personal data)
I'll go back to catch up now, good luck!

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[Burkey]

Any evidence of contact with the coil covers? Mine clearanced itself out over the first few months against the cowl brace. Of course, I'm on stock mounts...

I don’t have the coil covers fitted and the brace has been cut to provide clearance. No evidence off rubbing in that area either. Good idea though.

 

[Burkey]

I am just jumping in here late without having a chance to read prior pages but I am assuming 93 octane, have you tried better fuel from a Mobil or a BP?
Sorry if this has been covered already but I battled this early in my build when using Kwik Trip 93. Per Lund, I drained it and moved to Mobil and my knock sensor loved it immediately giving it full timing.
I also used Boostane with great results. This DOES 100% show improvements if octane is your problem. (from my repeatable personal data)
I'll go back to catch up now, good luck!

I’m not suspecting the fuel at this stage.
I’m using the same outlet I always use, never once had a bad batch in the 3 years of going there. I’ve put two tanks through it also, 6 weeks apart. Highly unlikely that it’s bad juice but I guess it’s possible.
Thanks for the advice though, it’s definitely the next trick in the book

 

[SVT-DADDY]

Easy enough to drop in a little boostane or the like and cross that off the list.

I keep a close eye on my KR and ran into an issue where all of the sudden they were looking bad. I had only used 2 favorite gas stations. Dropped a little Boostane in, and it straightened right out.

Either they got a bad batch of fuel or I(gasp) put the wrong grade in. I drive 3 different vehicles, so I guess it could have happened.

 

[Burkey]

@SVT-DADDY @HRSEPLA
I know where you guys are coming from, 100%, and I appreciate the input.
The difference here is that I’m getting ALL the knock at almost no load.
Pic below captures it better.
Note the low rpm, low throttle blade angles/changes and the lambda.
So, it’s driving quite comfortably with spark in the mid 20*s, even adding some, suggesting the fuel is just fine.
Throttle blade cracks open just a few degrees and within milliseconds the timing falls off the side of a cliff.
The lambda value of ~1.00 shows that I’m not asking the car to go anywhere near full power, given that the target lambda for WOT is 0.80
The entire log was done at normal traffic speeds/acceleration and is littered with the exact same results.
I decided to try it this way because the WOT logs weren’t giving me the full picture.
My line of thinking is that the culprit is sitting VERY close to the engine and it only takes the slightest twist for it to become a problem.
Damned if I can find it though

 

[SVT-DADDY]

@Burkey Just saw this reply. Thats some crazy KR ratings you have going on there at part throttle.

Have you made any headway on it?

 

[Burkey]

@Burkey Just saw this reply. Thats some crazy KR ratings you have going on there at part throttle.

Have you made any headway on it?

Your timing is impeccable (pun not intentional).

Short version:
The car goes in for a new muffler today, but I’m not 100% convinced this will fix it.

Long version:
I started by looking at all the things that were different in the Edelbrock install vs Whipple (due to no false knock prior to install). No joy.
I migrated to the exhaust, again, nothing obvious to look at. Took to the exhaust with a dead-blow hammer, nothing....
In the end, I setup the Ngauge to show me lambda for both banks, spark and KR.
A very definite theme emerged.
The KR seemed related to the amount of pressure being developed in the exhaust AND seemed to be getting worse over time, to the point where timing would sometimes drop to AFTER TDC......
A little head scratching took place.
Back under the car with the deadblow hammer. Finally got one of the bullet style resonators to make a very slight rattle.
Removed the suspect section to isolate it from the rest of the exhaust and to inspect.
It appears that the early tune may have partially killed one of the bullets when it “backfired” shortly after the Edelbrock went on.
I’ll have results soon enough. Fingers crossed.

 

[Burkey]

@SVT-DADDY
Well, it wasn’t the exhaust. As shown in the pic, the perforated tube had actually broken apart, creating a very slight rattle, but that’s not the drama.
I also tried octane booster a few weeks back, just to be 100% sure of the fuel. No change whatsoever.
At this point, I’m going to say it’s the calibration. The fact that the STFT is sitting around 16% at idle is NOT good. I’m beginning to suspect that the tuner has fingered something in the tune.

 

[Nuked]

Any vacuum leaks? STFT sitting that high at idle sounds like a leak post throttle body.

 

[Burkey]

Any vacuum leaks? STFT sitting that high at idle sounds like a leak post throttle body.

Possibly?
At some points it’s adding a heap of fuel, at others it’s pulling a heap out.
Vac leak would constantly be trying to add fuel right? And, it would surely throw a code eventually?
A vac leak would only cause knock if it was running lean, which it isn’t...or at least doesn’t appear to be.
To me (as a non-tuner) it looks a LOT like a jammed up MAF calibration.
In essence, the car would think you have X air flow and try and model based on that. It would likely seek the wrong spark tables because all the load calcs are up the shit etc etc.
Thanks for the input though, I’m really not ruling anything out just yet.

 

[Torinate]

I’m sure you’ve went over the bypass valve, but could it be slightly ajar at times and not making a complete deal? There is a linkage on it as well, could it be binding at certain times? Did you use a clamp on the vacuum lines to it and the supercharger as well?

I’m sure this has been double checked, but all the good things to review were taken...

 

[Burkey]

I’m sure you’ve went over the bypass valve, but could it be slightly ajar at times and not making a complete deal? There is a linkage on it as well, could it be binding at certain times? Did you use a clamp on the vacuum lines to it and the supercharger as well?

I’m sure this has been double checked, but all the good things to review were taken...

Yes, clamps used on ALL vac hoses. The bypass appears to be working just fine when the vehicle is stationary.
May have to smoke test, just to rule out a leak 100% I guess.
Thanks for the ideas!

 

[SVT-DADDY]

@SVT-DADDY
Well, it wasn’t the exhaust. As shown in the pic, the perforated tube had actually broken apart, creating a very slight rattle, but that’s not the drama.
I also tried octane booster a few weeks back, just to be 100% sure of the fuel. No change whatsoever.
At this point, I’m going to say it’s the calibration. The fact that the STFT is sitting around 16% at idle is NOT good. I’m beginning to suspect that the tuner has fingered something in the tune.

Are you on the Edlelbrock tune, or a custom? Has the tuner weighed in on this?

 

[Burkey]

Are you on the Edlelbrock tune, or a custom? Has the tuner weighed in on this?

Custom tune. I’ve sent logs and queried a lot of what’s happening. Tuner insists that he has the right data in the tune.
Honestly, the fact that he doesn’t see an issue with the STFT’s is kind of disturbing.

 

[SVT-DADDY]

Custom tune. I’ve sent logs and queried a lot of what’s happening. Tuner insists that he has the right data in the tune.
Honestly, the fact that he doesn’t see an issue with the STFT’s is kind of disturbing.

That would bother me as well. Local guy or one of the big names?

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