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Discussion Starter #1 (Edited)
Hello All,
I have a 414ci SBF with an 88mm turbo that has a large exhaust housing. Trans is TH400, reverse manual w/ brake and Ultimate converter. Trying to get it to spool up a little quicker on the trans brake. I just had my converter adjusted some and that helped alot. It will spool up to [email protected],400 rpm in about 8-10 seconds.
I'd like to get this to happen in 4-5 seconds or better.

I have a classic fast and MSD 7AL-3 ignition box with three step capabilities. Only have a 42mm Racegate and basic electronic boost controller for now. Still have to install my new Precision 66mm gate, AMS500, bump box and CO2.

Only using the 2 step right now. When I get up on the brake and hit the two step it's very mellow. It just stutters softly. I've seen other turbo cars get up on the brake and start popping and going crazy. Is this doable with my set up? Is it necassary? I know getting the tune right while staging is important. Any suggestions will be appreciated.
 

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Your tuneup on the brake is terrible. Lean and mean on timing(high not low) and only resort to ripping out timing as a last resort. You should be able to make that much boost 1-2sec from grabbing brake and going on two step. I have 1.32AR twins and can make 12psi in 1.2sec. If tune is even close it should make that much boost in half the time. What is your launch boost in the AMS ?? You are murdering the trans and begging for thrust bearing issues in the engine with that tuneup. If you are not comfortable tuning it do yourself a favor and find a competent local tuner to get you a baseline tuneup and tweak from there.
 

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^^^^ this.... His advice has me making 12-14psi in less than 2 seconds with a smaller engine and bigger turbo...
 

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Discussion Starter #4
Your tuneup on the brake is terrible. Lean and mean on timing(high not low) and only resort to ripping out timing as a last resort. You should be able to make that much boost 1-2sec from grabbing brake and going on two step. I have 1.32AR twins and can make 12psi in 1.2sec. If tune is even close it should make that much boost in half the time. What is your launch boost in the AMS ?
I have not installed my AMS500, 66mm wastegate or CO2 set up yet. I believe this to be some of my problem. My gate may be opening, slowing down the process. Not sure though. Really just running on wastegate spring right now. I have a AEM true boost hooked up, but doesn't do much because of the small 42mm single gate mounted in a poor position. It makes around 20-22lbs of peak boost whether boost controller is on max or if it's turned off completely.

TurboII when you say lean and mean, can you be a little more specific? What do you consider lean, 12s? High timing 28?

I know my launch tune up needs work. I feel confident with a little advice I can get it right. I've been tuning for years with good results. Truck runs pretty good down the track. Been a best of [email protected] with crappie 1.49 60' weightning in at just over 4K. Made 1,105 rwhp in bad air just this Saturday on 21psi on our Dynojet 224.

So back to my original question, is the aggresive 2 step popping all in the tune? Or is it more of a specific 2-step? Can I get it to do it with my MSD 7al-3 and Fast classic? Do I need it to do that aggressive popping on the 2-step to build boost quickly?

I'm limited to about 28 degs max timing due to crank trigger placement. I didn't think this would be much of an issue on boosted set up. I also run E85 fuel if that helps. Appreciate any and all info.
 

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Hey Paul,
With my car when I hit the 2 step it starts slowly but the more boost it is making the more aggressive the 2step starts getting and will start popping. So basically starts out soft on the 2 step about 5psi, then by the time it hits 12psi boost (launch) it is popping and doing all kinds of shit faster and faster.
Make sure your hot side has no leaks and is completely sealed. Turbine housing clamps and compressor housing clamps. Any small leak will kill spool. I know cause I battled it for a while.
 

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My af is low high 12s with 30* spark till about 6psi or 1.1 load with advantage 3.
 

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Try it again with no line to the side port of the WG. If it spools up much quicker, you know you'll be able to speed it up with the co2 boost controller. It's the side port reference pressure that blows the gate open while spooling, not the pressure on the face of the valve.
 

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You are going to need more timing than that IMHO. Get the A/F right thru the range of the converter then try it on the 2-step. You cannot trust the WBO2 on the 2-step, during this the A/F will read way lean due to unburned oxygen and fuel. It's kinda hard to put into words, I just have to feel my way thru this part of tuneup and listen to what the engine is trying to tell me. Engines are a little like women, different ones require a little adjustment of the formula to get them going, LOL!! The good thing is engines are logical and respond accordingly to changes where women are crazy as a run over dog. Hope this helps.
 

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From the few tidbits I'v picked up along the way, It is my understanding guys were pulling timing out on the 2 step.
Retarded timing=heat in the exh= quicker spool?
Just throwing it out there.
 

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From the few tidbits I'v picked up along the way, It is my understanding guys were pulling timing out on the 2 step.
Retarded timing=heat in the exh= quicker spool?
Just throwing it out there.
Depends a lot on the converter. If you have a tight converter and try to pull timing most times it won't make enough torque to get up on the converter or make it a very drawn out process which usually ends up with short transmission and thrust bearing life. Timing is pulled not so much to make exhaust hotter but to dump part of the igniting mixture into the pipes and closing the exhaust valve so all the force of the pressure wave is directed at the turbine. I wouldn't pull any large amount of timing unless it's a last resort. It can be very hard on the valvetrain and if done like the clutch guys do it basically taking all the advance out of it to make a bigger boom in the pipes has been proven to drop exhaust valves even with the best valvetrain parts. Proceed with caution.
 

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You need timing to get up on the converter, but once you're there, you can pull timing to increase boost, as long as it will stay up there. It doesn't take much timing pulled to add a little boost, at least on the stuff I work on. You can pull a whole bunch, but it will never be like a manual setup. Depending on the type of 2 step you use, reduced timing can make the motor even lazier on the 2 step though (increased hysteresis), but it still does the job. If it gets too bad though launching can become inconsistent. I've see up to a 1000 rpm swing, which is ridiculous of course.
 

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Depends a lot on the converter. If you have a tight converter and try to pull timing most times it won't make enough torque to get up on the converter or make it a very drawn out process which usually ends up with short transmission and thrust bearing life. Timing is pulled not so much to make exhaust hotter but to dump part of the igniting mixture into the pipes and closing the exhaust valve so all the force of the pressure wave is directed at the turbine. I wouldn't pull any large amount of timing unless it's a last resort. It can be very hard on the valvetrain and if done like the clutch guys do it basically taking all the advance out of it to make a bigger boom in the pipes has been proven to drop exhaust valves even with the best valvetrain parts. Proceed with caution.
dropping ext valve is that a convertor car issue ???
 

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Post up your timing map if you could
 

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Jim I think it has been a random problem with anyone that is truly "cannon firing" the engine by pulling all the advance out and even firing the plug ATDC. There are other things like weak or not enough spring pressre, valve to piston clearance, etc that when coupled with a exhaust pulse big enough to try and blow the valve back open can cause enough backlash in the valve train to break parts up to and including upsetting the retainer and lock enough to drop a valve. I know Moran was one of if not the first to try this and on the engine done no less!! Kurt was there and said it broke valvetrain parts wounding the engine pretty badly but Mike was happy because the theory was proven, it built boost crazy fast and a lot of it then just needed to figure out how to not break the engine every time you did it. Pretty sure all this was on John Meany's dyno. How is the 481X setup going?? Any good passes yet??
 

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Yep, I agree you need way more timing than that. My current SBC combo, I'm at 38 degrees for spool up and on some of my older ford motors have ran into the 40's! I'm a believer that when a car is on the two step, high timing does not hurt the engine no matter what the boost is! But the wastegate is most likely opening as well if it has a soft spring in it and it is creeping up. Like others have said, pull the line off the wastegate and try it on the transbrake only to see what happens. Only do one thing at a time.
 

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Jim I think it has been a random problem with anyone that is truly "cannon firing" the engine by pulling all the advance out and even firing the plug ATDC. There are other things like weak or not enough spring pressre, valve to piston clearance, etc that when coupled with a exhaust pulse big enough to try and blow the valve back open can cause enough backlash in the valve train to break parts up to and including upsetting the retainer and lock enough to drop a valve. I know Moran was one of if not the first to try this and on the engine done no less!! Kurt was there and said it broke valvetrain parts wounding the engine pretty badly but Mike was happy because the theory was proven, it built boost crazy fast and a lot of it then just needed to figure out how to not break the engine every time you did it. Pretty sure all this was on John Meany's dyno. How is the 481X setup going?? Any good passes yet??
We ran zero on the 2 step with clutch car with SBC on gas and alky for many many years.We dropped one stainless ext valve in all that time i figured 5 years @ 9400 was the culprit lol

we could build 24 psi in 1 second

481X is going good best so far is 4.13 @186 40 psi. Working on the 330 now only running 2.80 SBC ran 2.70 so it should be a beast when its sorted out running 4 speed and clutch may drop a gear in the future clutch car motor is very happy now its been a fun project so far
 

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My ECU has the option to cut spark, fuel, spark & fuel or soft for rev limit on Tb. I've tried all 4 options and with just cutting spark it will cannon fire out the exhaust.
 

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Yep, I agree you need way more timing than that. My current SBC combo, I'm at 38 degrees for spool up and on some of my older ford motors have ran into the 40's! I'm a believer that when a car is on the two step, high timing does not hurt the engine no matter what the boost is! But the wastegate is most likely opening as well if it has a soft spring in it and it is creeping up. Like others have said, pull the line off the wastegate and try it on the transbrake only to see what happens. Only do one thing at a time.
Would you still consider this okay with the LS motors? I am at 31 degrees while on the 2 step but worries me to ad anymore. I am trying to spool on the brake 2 step which is set at 3200 and bumping in and then when I set the transbrake it 2 steps at 4500. Tonight I was going to try leaving with more rpms. With my glide I could build tons of boost but with my TH400 I am at 4lbs of boost leaving even with 10lbs of CO2 for the launch. My convertor is a PTC 3400 so not sure how high to set my 2 step and still be safe for launch. Figured tonight I might try as high as 5k. Any thoughts?

Last night at TNT it ran a [email protected] with a 1.45 60ft leaving at 4500 on the T brake, 31 degrees timing, and 4 lbs of boost even though I had 10lbs of Co2 commanded for the launch. 295/65 MT ET Street Radial. Launches with no spin.
 

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Hello All,
I have a 414ci SBF with an 88mm turbo that has a large exhaust housing. Trans is TH400, reverse manual w/ brake and Ultimate converter. Trying to get it to spool up a little quicker on the trans brake. I just had my converter adjusted some and that helped alot. It will spool up to [email protected],400 rpm in about 8-10 seconds.
I'd like to get this to happen in 4-5 seconds or better.

I have a classic fast and MSD 7AL-3 ignition box with three step capabilities. Only have a 42mm Racegate and basic electronic boost controller for now. Still have to install my new Precision 66mm gate, AMS500, bump box and CO2.

Only using the 2 step right now. When I get up on the brake and hit the two step it's very mellow. It just stutters softly. I've seen other turbo cars get up on the brake and start popping and going crazy. Is this doable with my set up? Is it necassary? I know getting the tune right while staging is important. Any suggestions will be appreciated.
Smoke the system make sure you don't have any leaks
Coat or wrap headers
Double wrap crossover
Find a good thick blanket for turbo
Advancing the cam helps make boost faster

Testing
Set 2 step low at 5000
Set ams launch pressure to 20
Activate trans brake and slowly walk through rpms 3500-5000 should take 8-10 seconds to collect data
I would start and set the map to 12.75:1 a/f
Once the map is dialed in put your chip back in and retest adding timing
Don't be scared to put some timing in it
Once it gets to 2-4 psi it should move pretty quick if the tuneup is right
 
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