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| djxib | (tuning) - A few DOH!! Moments.... | ||
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Senior Guru
 
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All easy fixes but all brought me a WTH? DOH! moment..
Yes, running too lean will make the engine run hot. Yes, too much spark advance at idle will make the car hard to start. Yes, the O2 sensors will give you a really good idea whether you are lean or rich at tip-in. Stop guessing! Yes, a bigger cam will operate at a different MAP at idle. Oh BTW, this also means that the fuel pressure will be higher at idle. Oh, the fun of tuning... |
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Posted on: 2011/10/3 12:20
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Andy 1996 Greenwood Collectors Edition LT4 Previously 1992 Convertible Polo Green. 383 LT1/LT4 forged/balanced. V7-YSi, Alky. 608RWHP... Now sitting at a dismantler with a salvage title. Still runs... |
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| BrianCunningham | Re: (tuning) - A few DOH!! Moments.... | ||
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Senior Guru
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Why not have BlowerWorks tune it for you?
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Posted on: 2011/10/3 19:21
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Polo Green 95 LT1 6-spd http://mysite.verizon.net/vzevcp74/ 383 LT1/Vortech Supercharger/AFR heads/Rod end suspension/Penske-Hardbar dual rate coilovers/Wilwood 6pot brakes NCCC Governor: http://BayStateCorvetteClub.com |
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| mistaben | Re: (tuning) - A few DOH!! Moments.... | ||
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Senior Guru
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the probably wont do it if it is too old of a system...
speaking of tip in... do you have a wideband o2 sensor to get your a/f ratio correct? I haven't even tried tuning the part throttle on this '91. |
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Posted on: 2011/10/4 2:03
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| flyboy | Re: (tuning) - A few DOH!! Moments.... | ||
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Elite Guru
 
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Quote:
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Posted on: 2011/10/4 3:15
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| djxib | Re: (tuning) - A few DOH!! Moments.... | ||
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Senior Guru
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Quote:
Hi Brian - the tune is excellent for power and general drivability (Blowerworks are awesome). I had (have) split BLMs which was impacting tip-in and decided to fix it myself. Now fixed (although I've had to be a little creative). Car is not only great for daily driving but is a complete monster when I get on it. Just need to dial in my PE on a dyno - currently running 4800 RPM limit and 26 degrees max spark and a little rich for safety. Purpose of the post was to create a little amusement for the gurus  |
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Posted on: 2011/10/4 13:08
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Andy 1996 Greenwood Collectors Edition LT4 Previously 1992 Convertible Polo Green. 383 LT1/LT4 forged/balanced. V7-YSi, Alky. 608RWHP... Now sitting at a dismantler with a salvage title. Still runs... |
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| djxib | Re: (tuning) - A few DOH!! Moments.... | ||
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Senior Guru
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Quote:
Wideband bung and meter/logger being installed in a couple weeks so I can go to the dyno and can monitor things on a daily basis as the weather changes. To diagnose my tip-in issue I looked at my O2 readings - while they are not very accurate in terms of AFR I could see that it was trending very lean (i.e. less than 50mv both sides for about a second) so I was able to richen up the VE table under 1100 RPM (including down to 600) to improve things. |
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Posted on: 2011/10/4 13:16
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Andy 1996 Greenwood Collectors Edition LT4 Previously 1992 Convertible Polo Green. 383 LT1/LT4 forged/balanced. V7-YSi, Alky. 608RWHP... Now sitting at a dismantler with a salvage title. Still runs... |
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| BrianCunningham | Re: (tuning) - A few DOH!! Moments.... | ||
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Senior Guru
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Quote:
BlowerWorks specializes in the older cars. |
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Posted on: 2011/10/4 16:45
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Polo Green 95 LT1 6-spd http://mysite.verizon.net/vzevcp74/ 383 LT1/Vortech Supercharger/AFR heads/Rod end suspension/Penske-Hardbar dual rate coilovers/Wilwood 6pot brakes NCCC Governor: http://BayStateCorvetteClub.com |
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| djxib | Re: (tuning) - A few DOH!! Moments.... | ||
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Senior Guru
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I agree - they specialize in supercharging C4's.. |
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Posted on: 2011/10/4 16:56
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Andy 1996 Greenwood Collectors Edition LT4 Previously 1992 Convertible Polo Green. 383 LT1/LT4 forged/balanced. V7-YSi, Alky. 608RWHP... Now sitting at a dismantler with a salvage title. Still runs... |
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| mistaben | Re: (tuning) - A few DOH!! Moments.... | ||
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Senior Guru
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... so you are using the o2 sensor voltage to tell if you are rich or lean on tip in then? |
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Posted on: 2011/10/4 23:37
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| djxib | Re: (tuning) - A few DOH!! Moments.... | ||
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Senior Guru
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Yessir. Plenty of debate on the topic of using stock O2's for tuning, but you can definitely tell if something is trending lean or rich. You'll see the O2's cycle between 0 and about 950 mv as the car runs - this cycling is normal. At the low end it's lean, at the high end it's rich. Exact AFR for each millivolt reading might be car and brand specific, so you cant read an AFR from it. On mine, in the scan I could see the O2's cycling at idle and then they would peg at less than 50mv for a number of scan records when I trid to move away from a stop - definitely a lean tip in. |
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Posted on: 2011/10/5 12:35
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Andy 1996 Greenwood Collectors Edition LT4 Previously 1992 Convertible Polo Green. 383 LT1/LT4 forged/balanced. V7-YSi, Alky. 608RWHP... Now sitting at a dismantler with a salvage title. Still runs... |
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| mistaben | Re: (tuning) - A few DOH!! Moments.... | ||
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Senior Guru
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i will probably have to use this looking for lean condition on coming off of tip-in.... may be the source of my knock counts while driving.
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Posted on: 2011/10/6 0:39
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| djxib | Re: (tuning) - A few DOH!! Moments.... | ||
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Senior Guru
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Absolutely - very important to match up what was happening on the road with what you are seeing on the scan. E.g. find the key points on the scan where you accelerate. Watch the O2 mv and INT and BLM and Cell #s very carefully as you go through the scan - be suspicious if the O2 mv's stop cycling low/high/low and stay either at the high end (900 ish) or the low end (50 ish) |
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Posted on: 2011/10/6 2:32
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Andy 1996 Greenwood Collectors Edition LT4 Previously 1992 Convertible Polo Green. 383 LT1/LT4 forged/balanced. V7-YSi, Alky. 608RWHP... Now sitting at a dismantler with a salvage title. Still runs... |
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| mistaben | Re: (tuning) - A few DOH!! Moments.... | ||
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Senior Guru
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... btw this thread needs more updates on what your doing to tune your vehicle.
-> let me ask you how are you getting all the knock out? or do you not have that much of an issue? |
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Posted on: 2011/10/9 21:52
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| djxib | Re: (tuning) - A few DOH!! Moments.... | ||
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Senior Guru
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Quote:
I get a few hundred knock counts when I start the car, zero afterwards (even on high spirited scan runs). Here is what I have done so far to tune my car. Baseline tune from Blowerworks - got me close. (i.e. car started, idles, ran reasonably well). My car is very custom, lots of CNC work, so mailorder tune will be close but not perfect. Then used TTS Datamaster to do a ton of scans - my test drives were a whole combination of driving at certain speeds with the throttle held steady so I could see what was happening in specific areas with INT and BLM. Used VE master to get the tune roughly close to perfect then smoothed the table a little for cell transition. Lots of help from Greg at B/W. To be honest, the power stuff is easier because there are only a couple of tables. I usually make sure everything runs a bit fat (above 900mv O2) before I get to the dyno with a WB, and I limit the engine to less than about 4800 RPM. Even then the first few times I go into PE (i.e. above about 60% throttle) I double check for knock before I get on it some more. The hardest stuff (for me) has been tuning low down - I still have a rich condition at idle and a mild lean tip-in, but like I said it's all about carefully checking the scans - really carefully because you can miss a ton of stuff. I haven't had time to really get the tip-in perfect but I have driven 250 miles in the last 3 days and I love the way the car drives. When I get the dyno and install the wideband I'll tweak idle, tip-in and PE. Should be a monster! If you want, I'll take a look at your datamaster scans and I can express an opinion! Send me your .uni file at djxib@hotmail.com |
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Posted on: 2011/10/10 1:07
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_________________
Andy 1996 Greenwood Collectors Edition LT4 Previously 1992 Convertible Polo Green. 383 LT1/LT4 forged/balanced. V7-YSi, Alky. 608RWHP... Now sitting at a dismantler with a salvage title. Still runs... |
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| mistaben | Re: (tuning) - A few DOH!! Moments.... | ||
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Senior Guru
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k k. i haven't been using datamaster but ill try and do a run tonight email you. ty btw!
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Posted on: 2011/10/11 0:18
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| mistaben | Re: (tuning) - A few DOH!! Moments.... | ||
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Senior Guru
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ok I sent a copy of tonights datalogging. I didn't get to it last night... I think I got into fighting with my gf
 ... anyways with that said, I appreciate you looking at this, and sorry about not getting it out at a decent time previous night.i'm looking at this tip in stuff.... and A) the datamaster file has much superior resolution then tunerproRT at 10 shots a second. and B) I still don't have a clue what I'm doing lol |
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Posted on: 2011/10/11 10:40
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| mistaben | Re: (tuning) - A few DOH!! Moments.... | ||
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Senior Guru
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I just figured out how to get VE master to work tonight.... for some reason I kept mistaking the log files it was giving me. kept giving me junk/exactly what I put in.
its 4 am.. tomorrow i will turn off the fuel cut off and power enrichment... and maybe the tip in? and do a datalogg and see about just getting the VE tables strait. |
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Posted on: 2011/10/11 10:54
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| AKS_Racing | Re: (tuning) - A few DOH!! Moments.... | ||
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Guru
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Quote:
How much boost? That seems like a lot of spark advance, unless you are running some really inefficient heads, or have something special for the cam. Remember, you can loose power on the upper end with more advance than the combo truly needs. Aaron |
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Posted on: 2011/10/15 0:21
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Miss Nasty: Bigger SBC with C4SP and just shy of 30 psi boost. Low 9.0s with low 160+MPH with a decent 60' (1.72 is decent for me these days). :thumbleft: |
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| mistaben | Re: (tuning) - A few DOH!! Moments.... | ||
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Senior Guru
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... I didn't know that aaron, thanks.
the stock main spark advance table for my car for that year has up to 48* of advance... I finally started getting my knock counts down by going through and cutting out 10* off the top of the peak, and then dropping the rest of the table by about 5* everywhere.. |
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Posted on: 2011/10/18 1:18
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| djxib | Re: (tuning) - A few DOH!! Moments.... | ||
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Senior Guru
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Quote:
Thanks Aaron - at the moment only 5/6 pounds (controlled via RPM limit) until I can get a wideband hooked up. TBH I dont plan on touching the spark (yet). I'm also spraying 50/50 alcohol on a 2-stage controller that kicks in at around 5psi and then doubles flow at 10psi. Heads are CNC'ed LT4 heads, cam is a 236/246 with 1.6 rockers on a 115 LSA. |
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Posted on: 2011/10/18 1:52
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_________________
Andy 1996 Greenwood Collectors Edition LT4 Previously 1992 Convertible Polo Green. 383 LT1/LT4 forged/balanced. V7-YSi, Alky. 608RWHP... Now sitting at a dismantler with a salvage title. Still runs... |
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