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Flasher
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9,650 Posts
Discussion Starter #41
Oops, missed that he posted a timing map. I'd take a lot out everywhere for 16gs. I'd be around 8-10* at peak tq. 13-15* up top depending on how the car reacts and how much boost. Run more boost, less timing, more ethanol. You'll make a ton of power. If you run out of turbo and going max effort, then make dyno pulls, virtual dyno or track passes, adding timing above 6k to see if it picks up power or mph. Above 30psi, I'd start at 8* and 13* up top and go from there.

Point of reference, MBT on a single turbo car I tuned was ~13* up top. More timing picked up very little HP. Td05's may need a bit more to reach MBT, but I wouldn't start there when you have so much boost left on the table.

12* was about MBT up top on my LS at 20psi. I run 9* at peak tq.

A lot of 4G cars are 10-13* up top.

all ethanol examples

and give or take. some cars may want more fuel and can take more timing. Some less and less. etc. c16 cars and will be different

td04 cars will also be different
It appears you are on the money. I followed your advice and dropped the timing, left the boost where it was (although it was colder so it looked more like 28-29psi), and slightly leaned out the A/F. Made 4 pulls, quickly checking for coolant level change in between each, and it looked good. Temperature was solid at 170-180. Power dropped about 10-20 according to VD, however load reached a new high of 300-310. It was 280 before. Not sure what to make of that.

New timing map and VD:
287248

287249
 

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1G Foglights b!tches
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8,406 Posts
That curve looks better. I’d probably take a bit more out from 4-5500 and you might be able to add more timing at 5500 and up. But I’d get more ethanol content.

And rev it out! And add more boost up top only.

BTW you’ll eventually blow that gasket damage has already been done.
 

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1G Foglights b!tches
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8,406 Posts
BTW, you can also run it a little richer at peak tq. That’s your highest cyl pressures. Your map does the opposite of what I would do for longevity. Leaner and then richer. Swap them. Low low 11’s at peak tq (can even do high 10’s). Then mid 11’s up top if you’re car responds to leaning out. Not all do. Ethanol usually doesn’t mind being richer.

You’ll lose a little tq hit that 3Ser’s love to tune for, but you won’t be any slower down a track and the tune will be much much safer. The trade off of chasing that 20-50tq peak isn’t worth it at all. Make it up with optimizing the tune up top. You can still go too far but you can likely play with it without immediate consequences.

That said, You still have another 5-10psi in those turbos though, so I wouldn’t be chasing timing at this point anyway. And if you have a way to control the boost curve, start adding in duty cycle above peak tq and let them eat up top.
 

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Flasher
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9,650 Posts
Discussion Starter #44
Good news for my car! After a few weeks of refilling coolant after every time I drove, I got the idea to try a new coolant pressure cap. Reason being I noticed that coolant would come out of the overflow even at hot idle without ever driving it, as if nothing was holding it back. Turns out, I just had a bad cap. Now, after a dozen of passes, no coolant loss! Where previously, one pass and it was leaking.

I've turned down the timing and upped the boost some (just over 30 in 3rd) and made the AFR richer near peak tq. My plan is to increase boost to max, and then incrementally increase timing across the board and see what happens. I have plans with some local racers to rent the drag strip when they open back up, so hopefully I'll have some fun this year!
 

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Registered
1991 VR4
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790 Posts
Good news for my car! After a few weeks of refilling coolant after every time I drove, I got the idea to try a new coolant pressure cap. Reason being I noticed that coolant would come out of the overflow even at hot idle without ever driving it, as if nothing was holding it back. Turns out, I just had a bad cap. Now, after a dozen of passes, no coolant loss! Where previously, one pass and it was leaking.

I've turned down the timing and upped the boost some (just over 30 in 3rd) and made the AFR richer near peak tq. My plan is to increase boost to max, and then incrementally increase timing across the board and see what happens. I have plans with some local racers to rent the drag strip when they open back up, so hopefully I'll have some fun this year!
I had the same thing happen to me with deteriorated rubber on the cap seal. Love the easy fixes, but always wish you realized it earlier lol.

Also, 30 psi! Nice. Let's see a video of some pulls or track time :)
 
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