BEATAV8
The Engine Whisperer
- Joined
- Feb 14, 2002
Jas, This is a 6776 turbo with a PTC non lock on the foot brake. Slip on this setup was less than 7% @ 128mph.
New Converter Log attached (Too Tight)
- Thread starter blackgn1
- Start date
Jas, This is a 6776 turbo with a PTC non lock on the foot brake. Slip on this setup was less than 7% @ 128mph.
big reazon
Member
- Joined
- Nov 12, 2006
What is your stall rpm at 0 to 1 psi? Also you are holding a ton of boost on the footbrake. What is your brake set up?Jas, This is a 6776 turbo with a PTC non lock on the foot brake. Slip on this setup was less than 7% @ 128mph.
My 17 blade goes to 3000@zero with dex 3 and my 18 blade goes to about 3000@ zero with tractor fluid. Either will one will spool a 6776 as fast as in the videos posted. I like using a data log to look at because the needle doesnt usually keep up with the actual pressure when it comes up really fast. If hes getting less out of his maybe he needs to look at the timing and fuel in the ramp in.
I have low timing. 1-2 20 degrees. 3-4 18 degrees. I guess I thought the 9.5 was going to just bolt up and everything would be golden. Does the 9.5 spool and hit hard like the 10"? I changed converters for the track. Running around town blowing every car away is no longer fun. I just couldn't get into the 10's with the 10"
SCOOBY DOO
BASED CANADIAN PATRIOT!!
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- Feb 18, 2007
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BEATAV8
The Engine Whisperer
- Joined
- Feb 14, 2002
Yes it's a ball bearing. Same turbo / converter are now on a new motor with E85 and a much hotter cam and it's about the same as it used to be in that old vid.
That spool vid you have there looks good to me. Boost comes up and slip is less than 10%. Not bad at all.
BEATAV8
The Engine Whisperer
- Joined
- Feb 14, 2002
Stalls at 0 psi right around 2800-2900. Brakes system is stock powermaster with S10 wheel cylinders.
It took a little bit of experimentation to get the converter matched right. I had to swap it out and send it back to Dusty 1 time for a re-stall to drop it 400 RPM, which if I remember correctly was a change of 2 blades. It could technically go just a little tighter, but I don't think it would be worth it. It would loose some of the fun factor associated with the quick spool up, and all I would get is some better looking mathmatics for my slip % calculation and a car that ran just about the same at the track.
IMO if it can spool and it has less than 10% slip through the traps, there's not much wrong with that!
Here is one way I look at it (right, wrong, or indifferent)
The slipping of the torque converter to an extent is torque multiplication (less the losses inside the converter) so when your other stall was many more RPM's at a given boost.... it was multiplying the torque, the higher RPM's are making more CFM's available in the exhaust making the turbo spoolup faster..... and frying the tires.... downsides.... the losses inside the converter quickly become so much that the power you threw at it is lost inside the converter..... i.e. blowing through the converter..... this is where the ET gains will stop.... even with more power applied.
It is a balancing act..... PTC has become a staple of the faster Buick guys..... because they can usually build you a converter that is "loose enough" down low to make your turbo spoolup, but couples really well up top in the upper RPM's dropping TRAP RPM's but picking up the MPH.
In your case it appears on the surface yours is too tight, but it also appears you changed several things at one time. Now it sounds like you are backing up and planning on changing the downpipe back out to "see" if that has an affect.
The slipping of the torque converter to an extent is torque multiplication (less the losses inside the converter) so when your other stall was many more RPM's at a given boost.... it was multiplying the torque, the higher RPM's are making more CFM's available in the exhaust making the turbo spoolup faster..... and frying the tires.... downsides.... the losses inside the converter quickly become so much that the power you threw at it is lost inside the converter..... i.e. blowing through the converter..... this is where the ET gains will stop.... even with more power applied.
It is a balancing act..... PTC has become a staple of the faster Buick guys..... because they can usually build you a converter that is "loose enough" down low to make your turbo spoolup, but couples really well up top in the upper RPM's dropping TRAP RPM's but picking up the MPH.
In your case it appears on the surface yours is too tight, but it also appears you changed several things at one time. Now it sounds like you are backing up and planning on changing the downpipe back out to "see" if that has an affect.
I just pulled the log up and see the 3200 or so at 0-1 psi.... it would be interesting to see that it did at the track with a decent tune and some sticky tires.
I'd agree however.... it will probably be percieved as more laggy in town because it couples so fast..... instead of slipping. Reality, it will probably out ET and MPH the other converter 1st time out....
it may also seem a lot tighter on a non-downshifting throttle squeeze, since the 10" will probably give him a lot more RPM.
I'd like to see logs of his old converter vs the new converter. Say 50mph (so it doesn't shift to second) and see what the RPMs are.
The 9.5" converters really seem to change the shiftpoints (I haven't put mine in yet, I'm still on a 10", so this is "internet wisdom").
Other than a downpipe/wastegate issue and other tune related things, a valvebody change that would let the trans downshift at a higher MPH might help the happy-factor.
B
I'd like to see logs of his old converter vs the new converter. Say 50mph (so it doesn't shift to second) and see what the RPMs are.
The 9.5" converters really seem to change the shiftpoints (I haven't put mine in yet, I'm still on a 10", so this is "internet wisdom").
Other than a downpipe/wastegate issue and other tune related things, a valvebody change that would let the trans downshift at a higher MPH might help the happy-factor.
B
If the converter is close and the tune is there then the engine will be in the power band within a second from a roll and even less with a proper launch. With a 212/212 cam and 6776 this would be between 5000 and 5700. The sooner the engine gets in that range and the longer its there the quicker it will be if the car hooks.
On note from the last datalog.... I assume the main purpose of that log was to see where the stall is at a certain boost..... (up to nearly 4psi in this case)but if you wanted to see how quick it spools up.... you hold the brake and mat the gas..... not ease into it like you did on that log.
Yes I was just seeing how much boost it would hold. I have some logs I can post with the 10" converter. Boost and rpm came in fast. I have to put a lot of blame on the tune at this point. Are will all thinking the 206/206 roller is not enough cam for the 9.5 converter?
I agree with Brian.... it isn't the cam. If this were a n/a motor..... the cam/converter match would be much more critical...... in your case.... IMHO, it is not what is keeping spoolup slow.
Lean that puppy out some during spoolup some and throw a little timing at it......
Lean that puppy out some during spoolup some and throw a little timing at it......
What kind of fuel management are you using? I'm on the iOS app so I can't see your sig if its in there. If you are not using something that has a fuel/timing table you can adjust then you need to get some powerlogger files and send them to the chip burner so the fueling can be dialed in better. I've knocked up to 2 sec off of spoolup on different engines when adjusting the fuel and timing. If it's going to 3200 at zero with the 9.5" it should be coming in very fast. On the footbrake it would seem that it should start coming into boost before 3200 with the t67 compressor and 76 p trim especially with a .63 ex housing.
