New SMC user with some possible teething problems and questions

[GNVAIR]

I just recently installed a TA49 on my car along with an SMC kit at the same time. Although I dont usually like to make more than 1 mod at a time, I had the opportunity and the time to do it. I thought what the heck.
Anyways, I kept my JL 93 street chip (20 degrees of timing) for my 30's. I have been gradually raising the boost and playing with the pump speed and the turn on point. At 19lbs of boost I would get no KR. AT 20-21lbs, I have seen approx 2 in most frames on the Scanmaster and as high as 4.9 today in 2nd gear. I get no KR in 3rd, even at the top of the gear. My O2's are pretty consistant in the low 800's now. I have not played around with fuel pressure yet. My concerns are for one, I do noit like to see any KR when running boost over 20lbs. My 2nd concern is I am running the pump speed at MAX right now and cant get rid of it. I hear of other guys running upwards of 25lbs of boost on high timing chips on pump gas with no KR. Am I missing something here? Should I pull timing out of it or add more fuel? I know my 30lb injectors will soon reach their max, but at this time I am not seeing that. It just doesnt make any sense that I would get the KR in the lower gears and not in 3rd......which would be the highest load gear.
To add another variable, I just added Race Jace's Power Plate to the mix and it didnt make any difference as far as KR suppresion.
If anything, it feels slower by the seat of the pants.
Any help would be greatly appreciated. TIA

 

[Roc87]

What kind of alky are you using? I'm using denatured and have run as high as 25#'s of boost (Before my actuator started getting weak, now it'll only push 21), but that was with 19.3 degrees of timing. That was with pump speed around 6 - 7. I tried increasing the timing in the chip to just 20.0 and I started getting knock, even with pump speed all the way up. Even with pump speed at 6, the only knock I'll see is the turn on point. Which when I installed the NGK UR5 plugs, seemed to go away. Transition knock seems to be typical by what I've read on the board.

Just a guess, but I'd say you need more fuel.

 

[Otto J]

right off the bat i would dump the 30lb injectors and go get yourself a set of 42.5s read my sig i can get 20-21 lbs on pump fuel witout the alky running at about 21Degrees timing
with test with alky when it arrives
ojp

 

[WSLN 6]

Why would he be out of injector with the O2's in the low 800's?
I was running about 22psi on my stock combo(sig) and had to keep cranking down my fuel pressure to get the car running a little quicker.
I was only running 39psi vac off on the stock injectors.
Hey GNVAIR, just for fun, turn down the boost a notch or two, and crank the fuel down with it. My buddies car really seems to run best around 750 O2 on pump gas/alky.
Only takes a few minutes to try........

 

[GNVAIR]

I am running denatured with a small shot of WD40. I tried it last night and turned the turn on point up a bit.
I still get slight KR in 1st and 2nd, but I am starting to think that it might be transitional knock. I stayed in it in 3rd gear last night and got 0 KR, the O2's were at 760 at 21lbs of boost. It felt like a rocket. My fuel pressure is at 41lbs (vacuum off). I am a little afraid of going for more boost with the smaller injectors since the limit might come up rather quickly. I was thinking of turning up the fuel pressure some to get the O2's back up into the 800's again and then turning the boost up 1 or 2 lbs. What do you guys think?

 

[WSLN 6]

You are on the right track(no pun...) now. Raise the fuel pressure 1 psi as well as the boost. Take a run and watch for KR. Right around 760 O2's the car will fly, so try and make the mid to high 700's in your O2 counts your goal, but not at the expense of knock.
I wish I could lean my car out that far. For some reason, I can't even get the O2's close to that low. Oh well, good luck to you!

 

[Wolfj359]

I have found that leaving the alky on max setting and taking out fuel pressure works best. At the same time you are leaning out the mixture and increasing the octane of the fuel that is ignited. Think about it............the less 93 octane you mix with all the alky you are spraying the higher the overall octane will be. I have found that to be the key to tuning my smc kit, along with perfectly setting the spray on point. So far I have been able to obtain 23 psi boost on 93 octane with denatured alky and 26* timing race chip.

 

[Turbocars]

O2 #s are just a guide, especially with the alcohol cars. Tuning should be based on knock and EGT. I barely pay attention to the O2 #s in either cars. I don't blow head gaskets which are GM along with GM head bolts and I run LOTS of boost.

I also noticed that some of you are running some fairly high timing chips. Lower the timing and raise the boost with a race type chip for best results. A street chip typically will not have the fuel curves necessary for high boost.

Hank

 

[turbolimited]

Originally posted by Turbocars
O2 #s are just a guide, especially with the alcohol cars. Tuning should be based on knock and EGT.
Hank

Yep! Ever wonder why Steve also sells an EGT meter? In fact, I've seen a car on alky with O2s in the low 800s and egt was over 1500! Was the car rich? I think not. O2 value can be very misleading.

 

[blackshoebox]

Originally posted by GNVAIR
I just recently installed a TA49 on my car along with an SMC kit at the same time. Although I dont usually like to make more than 1 mod at a time, I had the opportunity and the time to do it. I thought what the heck.
Anyways, I kept my JL 93 street chip (20 degrees of timing) for my 30's. I have been gradually raising the boost and playing with the pump speed and the turn on point. At 19lbs of boost I would get no KR. AT 20-21lbs, I have seen approx 2 in most frames on the Scanmaster and as high as 4.9 today in 2nd gear. I get no KR in 3rd, even at the top of the gear. My O2's are pretty consistant in the low 800's now. I have not played around with fuel pressure yet. My concerns are for one, I do noit like to see any KR when running boost over 20lbs. My 2nd concern is I am running the pump speed at MAX right now and cant get rid of it. I hear of other guys running upwards of 25lbs of boost on high timing chips on pump gas with no KR. Am I missing something here? Should I pull timing out of it or add more fuel? I know my 30lb injectors will soon reach their max, but at this time I am not seeing that. It just doesnt make any sense that I would get the KR in the lower gears and not in 3rd......which would be the highest load gear.
To add another variable, I just added Race Jace's Power Plate to the mix and it didnt make any difference as far as KR suppresion.
If anything, it feels slower by the seat of the pants.
Any help would be greatly appreciated. TIA

Sounds like transition knock. I'm going to be changing my plugs to the ngk ur5's withing a week and gappig then to a tight .32 instead of the ac43's im running gapped at .35 to see if that corrects the problem. IVe expercience the same thing running a red93 chip(which is hell rich on the bottom end, running 19-21 psi. At the top of third, with o2's 800++ i get no knock, and i run 009's that are set a 43-44 of the vacume at ideal. I'd rather be a little rich and safe, then lean and sorry.

Also, has anyone experienced if your rolling in third at 35-40 and floor board the car, if the car drops down to second gear and then naturally shifts itself back up into third, do u get a rather scary amount of transition knock, like ive seen 39% and almost s%$T my pants. Guessing the load on the motor from the downshift magnifies the transition knock?? Also if u don't get into boost alot, i have got into the habit of primming the kit, if i think im going to race, I just "wet the lines" a little bit, seems to help with transition knock a little bit.

Shoebox

 

[turbolimited]

Re: Re: New SMC user with some possible teething problems and questions

Originally posted by blackshoebox
Also, has anyone experienced if your rolling in third at 35-40 and floor board the car, if the car drops down to second gear and then naturally shifts itself back up into third, do u get a rather scary amount of transition knock, like ive seen 39% and almost s%$T my pants. Guessing the load on the motor from the downshift magnifies the transition knock??
Shoebox

Yep, I get that occasionally. Kinda scary huh?? I am stumped as to the cause, and it has to be false knock. At that high of a retard value it should sound like driving down a gravel road at 100 mph if its real detonation! It shouldn't be transitional knock either, because I've seen the same phenomena before I installed alky. I can hear the knock and ping in 3rd gear if I'm running a little too much boost and those retard values are less than 4. Maybe valve train noise at high rpm?? I dunno.

 

[ez at nova]

I don't have alchy (yet!) but my GN does the same thing...floor it in OD or 3rd and when it downshifts I can show anywhere from 4 to 30 degrees of knock. Scares the crap out of me and I lift as soon as I see it...but like what others are saying here...maybe it's false somehow. Although, I have had it get very "bumpy" in the engine once or twice in the 1 or 2 seconds it occures, so maybe it was real.

Jeff C.

 

[blackshoebox]

Well, i guess im not the only one, any of the buick "guru's" on here have an answer for the question, is it fake KR or really when the car naturally downshifts itself and then "explodes" back into the higher gear shortly after your at WOT?? If it is real ill be shifting my car, anytime im going WOT.

Shoebox

 

[Steve Evans]

i'M JUMPING IN HERE A LITTLE LATE BUT NOTICED COMMENTS ABOUT "TRANSITION KNOCK"
AS WELL AS KNOCK WHEN YOU SMASH IT FROM A ROLL. aLL OF WHICH i AM SUFFERING FROM.
WHAT EXACTLY IS TRANSITION KNOCK, AND HOW WOULD CHANGING TO A DIFFERRENT PLUG CURE IT?
I WOULD LOVE TO BE ABLE TO FIGURE THIS OUT.
TIA

 

[turbolimited]

Transitional knock happens when your boost spools up and the alky hasn't reached the fuel mixture in the combustion chamber yet. You get knock.

This isn't to say that your alky isn't spraying yet, it just hasn't reached the combustion chamber by the time your boost is up in the "danger" level. I solved this problem by turning my trigger point down to about 11 psi. My pt-51 hits pretty hard from 6 psi and up, but my alky seems to get there in time when it starts spraying at 11 psi. I am running 25 psi with Red's street chip ~ 21 degrees of timing and ngk ur5's. I don't know if changing plugs will eliminate transitional knock.

Problem with turning the trigger point so low is that the car will sputter at half throttle because the alky is spraying with only 15 psi of boost. So its either moderate driving, or balls to the wall.

 

[blackshoebox]

"I am running 25 psi with Red's street chip ~ 21 degrees of timing and ngk ur5's."

What are you gapping your plugs at?

Shoebox

 

[Roc87]

I'm running a custom burned chip w/ 19.5 degrees of timing and also using the NGK UR5 plugs. I have mine gapped @ .033 and running around 25 PSI of boost. Turning the pump speed up, seemed to Drown out the motor and kick the boost back to 21. So I turned up the turn on point to around 14, and put the pump speed between 6 and 7. Just need to hook up the DS and keep turning up the boost and pump speed until I get knock I guess

 

[Ed Miklavcic]

knock....transition?

I installed the SMC kit in August and immediately registered 5 greens and 3 reds on my knock sensor. I have looked at simple causes of knock ie. exhaust pipe hitting, oil in intercooler, and simply have put my brain on winter rest trying to solve a problem.

My final solution was to replace my head gaskets because I have on occasion discovered a "rising" dip stick (new egr valve has been tried). No, I have no oil in my antifreeze and vice-versa. Performance has not been effected by the knock so I was stuck.

Now I read that transition knock awaiting alky to reach the cylinder may be all I've been experiencing. Give me a break, I have dialed down to 17# of boost with alky on at 12# and volume at 6, still a christmas tree full of lights. Is the answer or should I go back to winter meditation?

 

[Otto J]

same problem here it seemed to give me more detonation on less boost than i had before

 

[Addicted2boost]

I just installed my SMC kit last weekend as well. I just went to the track saturday and had the same problem as you guys, knock on launch and straightens out by top of third. I have my turn on point at 10 psi boost and the speed is about 7 currently. I did turn the boost up to 19 psi and 10 on pump speed at the track and still knocked. Although I have 30 over and heads slightly milled. So I need more octane now. I still need more time to tune this thing though. I'm no expert since I just installed this kit, but I think if the knock goes away at high rpm running 18 psi boost, then maybe it's a temporary rich knock we're all getting because the pump flows the same at lower rpm as when high rpm occurs. At times my car is popping when getting on it and I just think it's to much going into the engine until the upper rpm's can handle it. Also we see knock in first and second and starting the middle of third, the knock starts going away right? Well we get through first, second and part of third pretty quick, again right? The rpm's are going up and down really fast and we do have a very slow update from our ECM. Well we stay in third in upper rpm's alittle longer than first and second due to the transmission gearing obviously being higher and you can really take notice of this kit killing knock in 4th gear because the engine is in upper rpm all the time. I HIGHLY agree with WolfJ359 that leaving the alky on 10 and turning down the fuel would help because of more octane rating. But thats only if your running pig rich you can adjust. I also highly recommend everyone to prime their alky before making a run because I don't think alky stays in the line up to the nozzle due to no check valve. I'm also thinking maybe there should be a tps reading to the SMC computer because we may get to 3/4 throttle and need alittle less alky running into our engines as apposed to the same flow at WOT. What does the NGK UR5 plugs do? Also what is transitional knock? The engine being jarred around making false knock?