Tuning question- timing with 21* Trickflows

**Badazz96z28** · 06-02-2017, 06:06 PM

Those of you running the LE ported 21* TF heads, what's your timing table look like? Do you typically need more timing with better heads, or less timing?
Also when looking at the 2 Main Spark Advance tables, should the 4000 lines match on the 400-4000 & 4000-7000 tables?

Build Details:

- Refreshed bottom end. Stock crank/rods/pistons. Rods resized with ARP bolts.
- 11.5 compression .038 quench
- LE ported 21* Trickflow heads, 53cc, 2.055/1.60 valves
- LE cam 227/235 .569/.579 110
- LE ported LT1 intake
- BBK 52mm TB
- 36# FAST injectors
- XS Power headers
- FM 3/3-4 merge reduced back to 3" at axle and into Borla CB with open plate
- EWP
- LS1 air lid

Thanks

**Dirtybob** · 06-03-2017, 11:57 AM

Yes, you want the 4000 rpm lines on both tables to match.
I can't really say how much timing your motor will want, don't have any experience tuning modified LT1s.
The other thing that seems to confuse people is the "EST system time lag" which adds timing based on engine speed (5 or more degrees of timing at 4500+ rpm). It's located at address 0x12046 in my Tunerpro files but can be called different things (and have incorrect units - it is supposed to be microseconds acc'd to my info) depending on the XDF you're using. If it is set to zero then what you see in the tables will be what your car will run (at least for the high map/wot areas).

**96LT1355Z28** · 06-03-2017, 12:49 PM

I have 21* TFS from AI, with 12.5:1 and an LE LT1 intake on 91 octane (ethanol free) my power was the same from 29* to 35* so I've got 29* of timing. I'm on Holley EFI so I can't help you with timing tables.

**adam85** · 06-04-2017, 04:59 PM

Mail order tune for mine was set at 38* at the dyno he set it at 33* . No power difference between either. Just safer now.

**SSlowBoat** · 06-04-2017, 05:42 PM

depends on the motor. we have them on a boosted motor, so Lloyd shaved them to 54cc. we have 28* max at wot at 11psi. so it's a bit diffferent

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**Badazz96z28** · 06-05-2017, 09:28 AM

Over the winter I refreshed the bottom end, added the LE TFS heads & intake, reused the 227/235 cam that I already had. I knew going into it I'd be leaving some power on the table reusing the cam but will eventually change it down the road. I put it on the Dyno after some break in miles to get a baseline where I was at with the changes. At this point I was running a tune I had for the cam only set up, with only changes made for the bigger injectors & raised the rev limiter. The car made ok power (410/381), running a tad lean which wasn't surprising but had a weird dip up top so I wasn't sure if it was tune related since not updated for the heads & intake.

Shortly after the Dyno baseline I reached out to a guy with rave reviews in the LT1 community and supposed to be very familiar with LE packages. I sent him build details, Dyno graph, and log from Dyno run. I get his tune via email, load it into the car and hopeful to see an improvement over the baseline I had. I get the car back to the same Dyno and end up losing power (397/361). AFR was lean-rich-lean and had max 6* of KR in mid range. I was definitely disappointed but after making some fueling changes in his tune I was back to (408/380) before running out of time on the Dyno. After digging deeper into his tune, timing for the lines at 4000 don't match all the way across and timing peaks at 39*. I understand each engine is different and mail order tune isn't gonna get the most HP possible, but for someone that is a 'professional tuner' I feel it should of been much better than it was.

I've definitely learned a lesson, learn to tune yourself with the help of others that are knowledgeable and don't believe the hype from others raving about a tuner without seeing proof. I'd be willing to bet many of the ones complimenting this tuner have never scanned their car to see what's going on or have a before/after results.

Thanks for the help so far, I will make some changes to the timing table and hopefully find a little more power with this combo.

**superspirit** · 06-05-2017, 12:31 PM

I've definitely learned a lesson, learn to tune yourself with the help of others that are knowledgeable and don't believe the hype from others raving about a tuner without seeing proof. I'd be willing to bet many of the ones complimenting this tuner have never scanned their car to see what's going on or have a before/after results.

I see you have learned the same lesson I have. good luck!

**adam85** · 06-05-2017, 01:49 PM

If it makes you feel better i wasn't impressed at all when i took mine to the dyno. And it was a shop very popular with lt1s.

**Badazz96z28** · 06-05-2017, 02:00 PM

Originally Posted by adam85

If it makes you feel better i wasn't impressed at all when i took mine to the dyno. And it was a shop very popular with lt1s.

I hope it makes a nice difference at the track when the tune is worked out. From the cam only set up it picked up 40rwhp, 5lb of tq but the tq curve is much better than before.

**SSlowBoat** · 06-05-2017, 06:29 PM

Originally Posted by Badazz96z28

I hope it makes a nice difference at the track when the tune is worked out. From the cam only set up it picked up 40rwhp, 5lb of tq but the tq curve is much better than before.

I have same cam on stock bottom end rebuild thru t56 and made 383whp/373wtq, knowing my tune is questionable with le2 heads. if you made 410 with the trick flows id say it was worth it.

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