i see you got a tune from vector motorsports. would you recommend that place for a tune? i'm planning on getting one done sometime soon. if the tune is that far off i might go somewhere else.

 

I'm running a very similar combo (396 with LE2 heads, LE4 cam, 11.7:1 SCR, 8.8:1 DCR, .39 quench) and I run 34-35* of timing at WOT on 91 octane.

 

I think your leaving alot on the table with your setup. Why in the world would he setup your timing like you were running FI?. I also think your getting false knock as well. Good luck with the setup.

 

Thanks for the info. Hmmm.....

Sure I'll send you the tune. I have a feeling that would benefit me more than you anyway. Can I do that with Tunercat, or TTS? Don't have either yet, but I plan to buy Tunercat anyway. I did get Freescan working again, though. If you don't mind telling me how to copy the tune, or even suggesting a couple search terms to get me on the right track, I'll save the tune and share it with you. I'd happily show you a log file as well. I can sorta tune carbs and distributors, but haven't messed with e-tuning yet.

 

Normally I would expect 34-37° total advance at WOT for best power numbers.

I'll have to look at the DCR on that too see where you are here. What brand of gas are you using anyways? 12.5:1 SCR is pretty high even for a LT1 but I've seen guys pull that one off.

Bret

 

I was very happy with the Vector tune for WOT, and I can't argue with the numbers. Remember, this is on a Mustang, with mech WP. But, you guys are makng me wonder how much more there is. Alot, I hope. Now how to find it......?

His base tune still had full timing and was WAY lean, though. He knew the compression was high, even said it was too high, but didn't pull timing. I'd get a base tune by mailorder if you have a new motor and need a tune for break-in and debugging, then maybe let him do the dyno tune. I would not get a base tune from Vector if you need that, too. I had a few shiny ***** on the plugs at first check. Price was ok at $400, including the base tune. Not having A/F data recorded is also a major drawback. I said earlier it went to 12:1 at the high end, but I can't remember for sure , and I wish I had the data. Oh, and he couldn't connect to my car. Luckily I had my AKM cable with me, and that worked. Almost cost me 1/2 day vacation for nothing. Vector does a lot of LS1s with blowers, etc. VRE recommended them.

Well, he just tuned the timing the car wanted, and when he was done, the timing was at 20, which he said was like a blower tune. He didn't start out planning to make it that way.

Maybe there is still false knock, I'll try again to make it go away with high octane now that I can log again. I logged a file today (cool weather this morning, like the day he tuned it) and I was back down to only 3* retard at WOT, like on the dyno. Plus an occasional bit of retard at idle. On 94 octane pump Sunoco this time.

THANKS - Better late than never:
Thanks to all you CZ28 guys for your interest and continually helping me figure this out. And, especially, thanks again to Lloyd & Bret. Also to VRE - I have never run across somebody in the aftermarket auto industry as sincerely committed to giving the customer what was promised as Eric at VRE. There were a couple little glitches, nothing too major, and I practically had to beg him not to send a truck to get my motor and bring me a new one. He settled for just giving me some free parts. I can wholeheartedly recommend VRE as a good shortblock supplier, and Eric as a man who will stand behind what he commits to!

 

Hi Bret. I appreciate you looking into this, too. SCR and cam are per your recommendations(383, Mahle flattops and 55cc chambers, .039 quench), which we discussed a lot because I thought the compression was too high at first. Even if I can't get the timing up there, I'm happy with the current results. Fuel was always BP 93, even for the tune. I wanted to tune with that, then run Sunoco 94 when I can get it, to have a little margin of safety. When I ran on higher octane to test for false knock, it was the BP 93 with Torco Accelerator at 16 oz per 10 gallons or so. I plan to try a full can of Torco Accelerator in Sunoco 94 (104 octane+) to see if I can get ALL the knock to go away. This weekend I'll do that if it isn't rainy.

The DCR of 8.84 at .004 IVC is based on my degreeing the cam and mapping it out, not from you. I calculated it with the program from here:
http://members.uia.net/pkelley2/DynamicCR.html

 

Tunercat is the software you want to be able to send me the tune. I think they have a program (winflash??) that you can unload and load tunes with, but not make any changes (and it's free). It's pretty self explanatory getting the tunes loaded and unloaded. Just go to 'tools' and then 'read pcm'. Give it time to read the program and then save the tune and email. If you wanted to do that, that'd be fine. TTS (Datamaster) is excellent for logging the car. I'd take a look at a log, too (freescan or Datamaster). Send me whatever you can.

 

Will do, Benji. Ordered Tunercat tonite, we'll see when I get the authorization. My latest log file is too huge to easily study/graph, but I'll make a new one tomorrow.

All,

I did plot some knock profiles, and I think the closed-loop tuning needs work! All the knock is at low TPS/low RPM. Will getting rid of all knock by pulling timing help non-PE torque? In other words, does the knock retard hurt power more than having the timing set low enongh to avoid knock in the first place? Like the retard overcompensates? Is running in retard harmful?

Here's what I mean, histograms of retard:
[IMG][/IMG]

 

Well, you've done an excellent job of documenting your KR problem, now let's see if we can pinpoint its root cause.

Go to: http://gnttype.org/techarea/misc/octanebooster.html

......and scroll down to "How to Mix Your Our Brew". Follow the directions there for either the Formula 1(Toulene), or Formula 2 (Xylene), race gas, (yes, this will make oxygen sensor safe unleaded race gas....as long as you use either unleaded 93 octane BP or Shell V-Power as your base gasoline); and make two(2) gallons of 102 to 104+ octane fuel. Don't be afraid to use proportions of either Toulene or Xylene approaching 50% for your two(2) gallons of "home brew" even though the tables stop at 30% mixes. You will be diluting your two(2) gallons of "home brew" race gas with some residual 93 octane gasoline still in your gas tank.

Remember one(1) gallon of 117 octane (i.e. pure) Xylene mixed with one(1) gallon of 93 octane unleaded BP or Shell gasoline.......will yield two(2) gallons of 105 octane unleaded race gas.

Now, wait till your gas gauge reads 1/8 tank, (or even less ) and dump in your two(2) gallons of "home brewed" race gas. Now drive the car under those same low speed/ light throttle conditions and.......if you have been experiencing "true" knock, (e.g. due to tooooooooooo much DCR causing your KR problems), they will "disappear" with this now, 102+ octane fuel mix. If you still see KR with this fuel mix in your tank, then start looking for other areas of "false" knock like.....oh I don't know there can be soooooooo many with a new shortblock/motor like, a bad piston wrist pin, broken ring, loose roller rocker, cracked polylock, broken valvespring, bent pushrod, etc., etc., etc.

By doing this with true 102+ octane fuel running through the motor, (which will support DRC's up to around 9.5-9.8 (depending on other atmospheric and engine temperature conditions)), you will eliminate any chance of KR due to actual fuel detonation in your engine. Once you know this.....you can focus on finding any additional sources of "false" knock.

Old engineer's saying....."One test is worth a thousand opinions".

 

Modern old engineer's saying..."A thousand (or ten) accurate simulations is worth more than one test."


Jon
an OLD engineer

 

97 6SpeedZ, nice to hear from you. I take it you don't believe in the Torco stuff. I did a lot of reading on the Torco Accelerator, and the 'Vette guys seem to think it works, but that is just hearsay. So a known recipe will be worth trying. I'll try that way once I find a gallon can of Toluene/Xylene someplace for a fair price. The 32 oz can of Toluene in my garage was about 7 bucks, so I need to find a better source to buy a gallon. Paint supply I suppose. I'll get on the phone now. Take care!

EDIT: Found it for about $16/gal at GNE. Good enough. Now to drive around all day burning off most of that tank of Sunoco 94 I just bought. I know, just siphon it, but where's the fun in that?

BTW, you have heard my engine, but not with the clutch pushed in. Sounds a lot better that way. I'll demo it at the Member Summit for opinions from all who will listen. I admittedly don't have the nice Singer sewing machine sound you do. Yet. I really want to drive this thing for a while before tearing into it again. I can read between the lines, and sure hope all my metal is still in shape.....

OldSS, that is very true, but the kew word is 'accurate'. It is sooooo hard to tell a good simulation from a bad one without test correlation. As I'm sure you know from experience, it takes a lot of testing to learn the limitations of even a great simulation software, and how to properly define the parameters, and the valid range for the results. More often than not, I find the predicted results from even OEM-grade simulations go awry due to bad assumptions if there is not a very experienced test guy running the simulations, and still testing once in a while to validate the results.

 

Good points, JP. Yes, of course "the proof is in the pudding".

What I have noticed is that if you stay close to an empirically documented (dyno tested) baseline engine, like say the LT1, even minor changes which show up in ECA (simulation) also show up on the dyno in very close agreement. It's when you are tring to "break the bank" and get out of the box that sims can either help you a ton, or bust your a$$.

The more understanding of how an engine works (vs. how we want it to work) an engine designer has, the better chance he has of getting the sim to validate or invalidate his ideas. A sim, like a paintbrush or a chisel is just a tool. As you said, it's the operator/designer/artist that makes those tools do something useful.

I like your sig picture. Are you associated with an OEM? You are in the right area.


Jon

 

Yup. I am. You can probably guess which one. Fun job there, advanced vehicles.

 

DC?

I was also in the 60s. You remember the 60s. They are in all the history books now. The Muscle Car era was fun, but vehicles today are soooo much better and faster.

Had a chance to talk with a prominent Powertrain head/intake guy (RS) who is a few years younger than I. We are alums of the same Mushroom Farm. A lot of things never change much: "platform folks vs. the powertrain folks" is still being played.


Jon