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Chupa Cabra
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Discussion Starter #1
I asked in another thread yesterday about my timing, and I really didn't want to keep asking questions in another person's thread so I decided to just post up the screenshot I have of my timing table from HPT to see what you guys think I should do to get this thing to 60' better and get to the 330' quicker. I trap 112 on the regular with 12-15psi at mid 11's afr.

Set-up is a stock block, stock bore, stock stroke 10:1 cr 346 c.i. LS1. Stock 853 heads, comp 918's, chromoly pushrods, Thunder Racing 227/224 114lsa Reverse Grind cam, LS6 intake, stock tb, twin walboro 255's, 60# mototron injectors, 4l80e, 3800 fti stall, and 3.55 gears on a 275/50/15 hoosier drag radial.

I know I've rung every bit of 60' and 330' out of this thing the way it sits. I've tried launching off the stall's highest stall speed with no two step, I've tried giving it a good 500-800rpm flash by launching at 3000-3200rpm and it just went slower to the 60'. In my videos, every single time the back tire crosses the 60' beam the car wakes up and just rockets to life. I'm guessing its the timing and just not being enough power soon enough to move my 3900# pig off the line the way I want it too. I had been trying to conserve the stock bottom end all season, but the season is over at the end of november and I'm putting a new motor in this winter and/or forging the current one.

Here is the timing table from hpt, any helpful advice would be greatly appreciated.

 

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Chupa Cabra
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Discussion Starter #3 (Edited)
PTE76GTS, 76mm compressor, 75mm turbine .96 a/r guess I forgot to add that, pretty important detail I left out there. It has truck manifolds iirc they are 1 5/8's primaries and it has a 2.5" cross over feeding the turbine, and a 3 1/2" downpipe that is then necked down to 3" all the way out the back.
 

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Chupa Cabra
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Discussion Starter #4
Also all hotside piping is wrapped, and I have a turbo blanket on the turbine side of the turbo so I don't think heat is the issue. Let me know what you all think.
 

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Chupa Cabra
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Discussion Starter #6
? Too small? I can't fit anything bigger than that in it's current location.

I guess I could unhook the exhaust before I go the track the next time, but it spools fine in 1st, 2nd or 3rd on the street and on the footbrake while staging, it's just off the transbrake it's a slug, then it just comes alive, almost like it is lugging against itself, not bogging, just no increase in rpm until 60' then bam it wraps right up.
 

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Chupa Cabra
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Discussion Starter #8
Yea i know it's hard to read I don't know why it came out like that.

I don't really have a good enough camera to take pictures of the time slips to post them up, as the printer at the track prints pretty lightly.

I can tell you my best pass ever e.t wise was a [email protected] 1.51 60', 4.33 60'.

Just looking at the timing table it only has 14* in it at the rpm it comes off the transbrake. At the rpm I am at when the back tires cross the 60' and it comes alive is 16*. I was also reading that most of people for racing set there timing to "normal" up to 4-6psi where as mine is really soft and no where near normal at 4-6psi, hell its softer at 4-6psi than it is at 15psi. I was thinking about trying 20-22* timing all the way up to 3200 rpm, then ramp it down to 16* at 3600rpm, 17* at 4000rpm, 18* at 4400rpm up to redline. I think that shoud really help with getting it moving off the line.

I just wanted to see if someone could say hey, "Start off with trying this much timing up until here, then pull x amount and ramp x amount back in to redline/shift point.

I was also thinking about Setting the timing at 14-15* from 3200 to redline, and then letting the IAT table add timing off the hit when IAT's are lower in 1st gear, and as they start to rise down track have it retard the timing as IAT rises in 2nd and 3rd.

I like both ideas, but would just like to know what you all think.
 

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Your timing table should be 28* or so with no boost and decreasing linearly with boost. It should not have less timing in it at 4-6 psi then at 15 psi. Going by your table it isnt commanding less timing at the lower boost levels, something else must be retarding timing like IAT, Burst spark, ect (unless you are maxing that table gram/cly at your launch boost level). Do you have a log of a pass with that same table in it?

Regaurdless of the timing...60'ing slow usually has to do with the car building boost. What psi does the car leave on at what rpm? and when on the track does it make the full boost? You are alittle overgeared for the power the car makes now so you need it to make more power sooner via timing/boost or gear it alittle more.
 

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How much boost are you building on the line in the log?

After you launch, does boost go down before it goes up in your log?

When you let go of the tbrake button, where do your RPMs actually flash to in the log?

With the Th350, I was RPM limited on the tbrake to 3500 RPM despite the converter being a 4500 FTI. So that's where I set my 2 step. I would build 6-7 psi on the tbrake/2step and cut consistent 1.29-1.31 60's at 3900#'s race weight.

I got rid of my HPTuners a while back and I don't have the software installed anymore on a computer but I do have my last tune file that I could email you if you want to see how I had my timing setup.
 

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Chupa Cabra
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Discussion Starter #11
Your timing table should be 28* or so with no boost and decreasing linearly with boost. It should not have less timing in it at 4-6 psi then at 15 psi. Going by your table it isnt commanding less timing at the lower boost levels, something else must be retarding timing like IAT, Burst spark, ect (unless you are maxing that table gram/cly at your launch boost level). Do you have a log of a pass with that same table in it?

Regaurdless of the timing...60'ing slow usually has to do with the car building boost. What psi does the car leave on at what rpm? and when on the track does it make the full boost? You are alittle overgeared for the power the car makes now so you need it to make more power sooner via timing/boost or gear it alittle more.

That table is completely maxed out the minute I go to the transbrake, I am only at .5 g on the footbrake, and it spools fine on the footbrake with high 20's low 30's timing. Once I'm on the transbrake I only get 13-14* timing.
 

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Chupa Cabra
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Discussion Starter #12
How much boost are you building on the line in the log?

After you launch, does boost go down before it goes up in your log?

When you let go of the tbrake button, where do your RPMs actually flash to in the log?

With the Th350, I was RPM limited on the tbrake to 3500 RPM despite the converter being a 4500 FTI. So that's where I set my 2 step. I would build 6-7 psi on the tbrake/2step and cut consistent 1.29-1.31 60's at 3900#'s race weight.

I got rid of my HPTuners a while back and I don't have the software installed anymore on a computer but I do have my last tune file that I could email you if you want to see how I had my timing setup.

On the line I footbrake to 5-6psi, and once I get 6 psi, I set the transbrake and I normally get 8-9 psi doing that. I have let it build 10psi before when I had the boost controller set at 11, and it still didn't 60' that much better maybe a tenth gained.

Boost always stays whatever the launch boost was/is at launch, but it just hangs there, until rpm's rise.

When I release the T brake I usually see 4400rpm flash.

Man if you could email me your tune file that be great Los. I know you have a little bit bigger turbo, and more cubes, but it would be a great reference point for me.
 

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On the line I footbrake to 5-6psi, and once I get 6 psi, I set the transbrake and I normally get 8-9 psi doing that. I have let it build 10psi before when I had the boost controller set at 11, and it still didn't 60' that much better maybe a tenth gained.

Boost always stays whatever the launch boost was/is at launch, but it just hangs there, until rpm's rise.

When I release the T brake I usually see 4400rpm flash.

Man if you could email me your tune file that be great Los. I know you have a little bit bigger turbo, and more cubes, but it would be a great reference point for me.
Well I can't email it without an email address.:smt083
 

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Chupa Cabra
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Discussion Starter #14
Also to answer Fast Track's question about rpm and boost, I dont' have a set rpm I always leave at on the two step because I have been playing with it a lot trying to get it to 60' better somehow someway and it just won't. I'd like to set it at 3200-3400rpm so I can give my stall a good flash when it leaves as right now, I've found setting the two step as high as it will go on the converter's stall is giving me the best 60', which still feels labored and that's been as high as 3800-3900rpm per hpt log's. I was using hygard lite then and now that I am using regular hygard I can only get about 3600rpm on the converter which is making my 60's worse. So I am pretty sure it has to be the low timing after seeing what most people are running and doing.

It leaves at 8-10 psi and doesn't hit full boost till right after 60'. I had 3.08 gears in the car, but I was going though the traps either on the limiter in 2nd at 6500 or shifting into 3rd 30' before the traps killing me e.t. and mph. I wish I had done 3.42's because I don't have enough gear to go through the 1/4 in my 275/50's. I have since then raised the limiter to 6800 so I probably could now, but I just don't like spinning the stock bottom end that high with the power I'm making until the forged 5.3 goes in or I forge this current motor.
 

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I just looked at it. Apparently I hadn't deleted the software but it isn't going to help you. It's been so long since I looked at HPT that I had forgotten that the ignition timing is vs cylinder air mass and not KPA. It's at 18* from 3K RPM up and from .80 to 1.0 air mass. That's as high as the 98 PCM would go. I think that I only ran the stock block on the HPT. After that let go I switched to the AEM and now I am on the Holley but haven't been down the track with it yet and it's set up REALLY soft.

Are you using CO2 for the boost control? I have 15 psi (launch stage) ramping to 40 psi on the top of the gate in like 2 sec starting as soon as I let go of the tbrake button.
 

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Chupa Cabra
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Discussion Starter #17
I just looked at it. Apparently I hadn't deleted the software but it isn't going to help you. It's been so long since I looked at HPT that I had forgotten that the ignition timing is vs cylinder air mass and not KPA. It's at 18* from 3K RPM up and from .80 to 1.0 air mass. That's as high as the 98 PCM would go. I think that I only ran the stock block on the HPT. After that let go I switched to the AEM and now I am on the Holley but haven't been down the track with it yet and it's set up REALLY soft.

Are you using CO2 for the boost control? I have 15 psi (launch stage) ramping to 40 psi on the top of the gate in like 2 sec starting as soon as I let go of the tbrake button.
I have the same table as you, mine is a 98 pcm too.
 

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I have the same table as you, mine is a 98 pcm too.
I'll send it to you when I get back home today, but like I said, I doubt it will be useful to you as it's pretty much 18* everywhere at WOT and my converter has been tightened significantly since then as I was only running 10.0's with the stock bottom end. It did 60' in the low 1.3-1.35 range back then also but the converter was flashing to 5300-5400 RPM.

In the mean time can you post some screen shots of a log showing RPM, MAP, AFR, MPH and TPS?
 

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Chupa Cabra
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Discussion Starter #19
I'll send it to you when I get back home today, but like I said, I doubt it will be useful to you as it's pretty much 18* everywhere at WOT and my converter has been tightened significantly since then as I was only running 10.0's with the stock bottom end. It did 60' in the low 1.3-1.35 range back then also but the converter was flashing to 5300-5400 RPM.

In the mean time can you post some screen shots of a log showing RPM, MAP, AFR, MPH and TPS?

Sure, let me see if I can dig some up. The only problem is when we went to data log, we didn't change the kpa over to map, and it stops at 104.
 
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