This is exactly what I wrote about in one of my earlier posts. There are no stupid questions or answers. The coin falls both way. I think that the best thing this forum should have to offer is answers for the beginner.This Turbo Buick community should be the beginners dream come true. That's why we shouldn't be allowed to call names. It hurts this community in at least two ways. People with good advice stop posting,and people who need help stop asking. If these two things happen,there's no usefull purpose for this site.
Wheel Spin Knock
- Thread starter GN HEAD
- Start date
Welcome!
By registering with us, you'll be able to discuss, share and private message with other members of our community.
- Status
mikestertwo
Well-Known Member
- Joined
- Sep 13, 2006
- Messages
- 5,249
To get back to the original post, my son sent me a DS file of his car during a hard acceleration run and saw something interesting. The knock count started just as the tires started to break traction. As the tires started to loose more traction, the knock count frequency went up. As soon as the tires broke loose completely the knock count stop! Now this is my humble opinion but I think the knock may be coming from "tire shake" hammering the drive line.
This is a very good theory. It is a very good guess as to why the knock sensor detects knock during wheel spin. This is exactly the kind of thing GN HEAD was asking for,theories as to the cause of the knock. It's also another good example of a real life experience that supports my guess that it is false knock. Thanks for the real data.
Russ Merritt
New Member
- Joined
- Aug 11, 2002
- Messages
- 2,715
I disagree completely and here's my real world/racing data.
In the TIA class in BG last year, I was driving a customers white T-type. It had a completely stock rear suspension, MT drag radials, and I was launching it off the e-brake/foot brake at roughly 15# boost ( 1.57 60'). It had what I call moderate/severe wheel hop and I was actually waiting for something to break and a direct result of it. It was "hammering" the driveline about as bad as it could, far worse than any wheel spin. Anyone who saw the car run I'm sure remembers it. Anyway, there was zero knock throughout the entire wheel hop/tire shaking event (All of 1st gear). The only knock I saw was in the 2/3 shift, roughly 2.3 degrees. It would go away and the car would run it's 11.30 @ 120. This was one of his 4 beaters and we weren't supposed to be racing this car or I'd have fixed the suspension.........
GN HEAD / Ttype6
When you are done wasting time figuring out how to spin em without knock (that I believe is real), try and find the missing 8 10ths/10mph in that car. Your leaving a lot of horsepower on the table in your quest to SMOKE EM UP!!!!!!!!
GN HEAD, I got kick outta the comment of how you think you have to tub your car and put GIANT tires on it to hook up..........That was a good one...
mikestertwo
Well-Known Member
- Joined
- Sep 13, 2006
- Messages
- 5,249
Knock is determined by frequency, not amplitude.
Russ Merritt
New Member
- Joined
- Aug 11, 2002
- Messages
- 2,715
Very true......
Pronto
No amount of evidence will ever persuade an idiot.
- Joined
- Dec 9, 2002
- Messages
- 16,810
Ok, I'll take a feeble stab. GN Head states that he can launch at the track with slicks and get good traction and no knock. He then states that with Nittos on the street he cannot lauch hard with out getting spin and knock. The only difference I see in the statements is the TIRES. I listened to Russ and went from a 1.85 to a 1.67 with switching from 235/60/15 to 275/60/15 BFG drag radials (thats what I happen to have and will get M/Ts at some point) at the track. I don't street race so I will use up my 235s and use the 275 when I go to the track. BTW I got no knock on either.
mikestertwo,we're on the same page.
This is a good example of how severe tire shake didn't cause the knock sensor to go crazy. Now we're compairing,real life,results.The more theories we can disprove,the closer we can get to the cause. You know,this is an example of,what you say is far worse than any wheelspin,yetyou saw no K.R. I guess this is an example of wheelspin without K.R. This is evidence of wheelspin not being the cause of K.R. in and of itself. As mikestertwo said,based on his D,S, file,There was a short period of time,during the start of wheelspin,that the K.R.was recorded. I wonder if this is the time when the vibrations are in the frequency that disterbs the knock sensor and the violent tire shake creates vibations outside of that range.
This statement you quoted shows that GN HEAD knows how to get the traction that stops the knock. He's not asking for advice on how to get traction,or how to stop wheelspin knock. He wants to find out what causes his knock sensor to detect knock during wheelspin? Are you saying that your knock sensor doesn't record knock during wheelspin?
So,are you saying that wheelspin,in and of it self causes knock, Can you tell us why this happens. Does it happen on all turbo Buicks? Does it happen on all race cars with knock sensors? It would seem that when you do a burnout before a race it would be a form of wheelspin. If your theory is true,this would create spark knock,after all,this is wheelspin. Since wheelspin is the cause of knock,and(as you theorise)the knock is real,Do you avoid doing a burnout before a race?
refer to post # 6
can you explain why the fast system don't pick up any knock during wheel spin? it uses the factory knock sensor and knock module so it should still detect all those vibrations and frequencies that are creating during the wheel spin action.
look a tad closer to the speed and LV8 tables and also the timing tables on the direct scan when this wheel spin occurs.
Your earlier post post was a good theory as to what might be causing the knock that GN HEAD sees during wheelspin. It's obvious that it happened to you because you recorded the incident. I don't believe you're making this up,and it makes sence. Your answer shows that you understood the question. You mention that the fast system doesn't pick it up. The factory setup doesn't pick it up on many cars either..It doesn't on my car. This is why I don't think wheelspin causes knock (in and of itself). If it did,every car would do it. The example you gave was one of real knock. If the majority of the cars that experience this problem did so because of the same thing you described,I think there would be alot of blown head gaskets as a result because your case was a case of real knock. I've read posts of many owners seeing 20 degrees of K.R. or more without hearing any audible knock. Even during burnouts. If the knock was real,you'd hear it at that level and be reluctant to do burnouts. This is why I tend to think that in most cases,including GN HEAD,It's false. I also think you ask a very good question.I don't know the answer.
talk about beating a horse to death
oppps ..forgot winter is here .. ok back to tubbing out this car to get some tires in there 
Pronto
No amount of evidence will ever persuade an idiot.
- Joined
- Dec 9, 2002
- Messages
- 16,810
Does it really matter why he gets knock? If he can eliminate it with traction then the easy answer it traction. Why split hairs? I can do my burnout at the waterbox with no knock. Occasionally I have had knock with spinning the tire but not often.
talk about beating a horse to death
Yep, i just ordered me some et streets to eliminate my knock. i could care less what causes it as long as i can get rid of it. Thanks Russ. on a side note my scanmaster never shows knock but the casper's knock gauge will when the tires break. i guess the knock gauge is picking up other sounds...Bob
I see that you edited this post from its original wording where you advised,either GN HEAD or myself to tune our damn cars. Are you saying that the knock is real and caused by a poor tune? If so,how did you arive at this conclusion? Are you saying that wheelspin,in and of itself isn't the cause of knock? My car doesn't need tuning it runs strong with no knock retard. My ET Street bias ply tires hook extreamly well after I heat them up. If I don't heat them up I can easily overpower them and create wheelspin. When I do this,I don't get any knock. From the earlier posts,I see no evidence that GN Head needs to tune his car,nor does he need help with traction. He stated that when he puts slicks on the car it hooks well with no knock.talk about beating a horse to death
It matters to him and many others. He's not asking for advice on how to eliminate knock. It sound like we can count you in as one who doesn't see knock during wheelspin.
It's ok that you don't care about the cause,just as it's ok that he does..I don't see an atempt in your post to offer a theory as to why tirespin would cause the knock sensor to detect knock when the tires break loose. Can I assume that,because of your statement about your knock guage,that you tend to think that the knock is false?
- Status
