Advancement of fuel delivery?
- Thread starter Alky V6
- Start date
I tried to slowly come up on power on my last run so I could concentrate on the BP gauge and the thing flooded when the aux fuel came in. The way this fuel system is setup, it's obvious that I have to be in it pretty hard for the aux fuel transition to come in right. I'll keep trying to get that number though. I'm thinking of fabbing up an inside camera mount.
The one glance at the BP guage I did manage during that run, it appeared to be a one to one ratio. 8 psi to 8 psi.
The one glance at the BP guage I did manage during that run, it appeared to be a one to one ratio. 8 psi to 8 psi.
Sorry Scott. No new "its" yet.
Scott Wile
I think you'd win that bet.
Who? Me? Scared? Scott, you're just too silly.:tongue:
The delay timer is not due in for awhile and I'm in desperate need for it. Yesterday took the car out and did mild launches. Two runs in a row I got tire chatter all through second gear. It may be time for tires. The next set will be taller.
I reduced the boost controller to 30 compared to the record making setting of 34 because one of the other racers warned me that the track was a little off. Still managed to click off a 5.84 @ 121.3 with the tires chirping the whole way. Video on the way. Not the best 60 foot. 1.4x. I have to start controlling the launch more precisely.
I reduced the boost controller to 30 compared to the record making setting of 34 because one of the other racers warned me that the track was a little off. Still managed to click off a 5.84 @ 121.3 with the tires chirping the whole way. Video on the way. Not the best 60 foot. 1.4x. I have to start controlling the launch more precisely.
Got the BP reading!!!
I started reducing boost today at the track. I'm just getting tired of blowing away the tires and not getting traction. It makes for a very nervous run. I ended up with the boost controller set at 22 psi. It gave me a very predictable feeling run and the tires actually held to the track for all of third gear. Even at 22 psi the car still clicked off a 5.9x @ 116.x mph on a soft launch.
On the second run of the car feeling stable in third, I peeked over and got that BP reading. It was higher than I thought it would be. 38 psi exhaust back pressure for an intake boost pressure of 22 psi. This is pretty bad, right?
I started reducing boost today at the track. I'm just getting tired of blowing away the tires and not getting traction. It makes for a very nervous run. I ended up with the boost controller set at 22 psi. It gave me a very predictable feeling run and the tires actually held to the track for all of third gear. Even at 22 psi the car still clicked off a 5.9x @ 116.x mph on a soft launch.
On the second run of the car feeling stable in third, I peeked over and got that BP reading. It was higher than I thought it would be. 38 psi exhaust back pressure for an intake boost pressure of 22 psi. This is pretty bad, right?
Don,
That over a 1.7:1 ratio. Anything over 1.5 and your giving up power. At 30 psi its probably worse. That why i suggested that the BP was pushing your gate open at that psi. The 76 wheel most likely has some left. That turbo could use a s trim turbine with your combination and maybe a larger A/R housing especially nitrous assisted.
That over a 1.7:1 ratio. Anything over 1.5 and your giving up power. At 30 psi its probably worse. That why i suggested that the BP was pushing your gate open at that psi. The 76 wheel most likely has some left. That turbo could use a s trim turbine with your combination and maybe a larger A/R housing especially nitrous assisted.
Good advice. I don't think I'll be doing anything to this turbo though. I'd change it out to a different turbo first. According to the compressor map, if there is anything left in the compressor, it's not very efficient. I don't like pushing equipment beyond limits. Can't you tell?:biggrin:
The way I see it now, my car is at the limit of turbo, tires, suspension and fuel system. All would need to be upgraded to go further by much with the ET and mph.
I'm going to concentrate on the 60 foot performance for now. Get the timers installed and work to find the best activation timing, ignition timing and mixture strength for the nitrous. Everything to do with the nitrous system has purposely been very conservative all this while. There is room to go to slightly smaller on the fuel jet, take 2 or more degrees out of the retard and move the shut off point to a higher map. I need to update the boost control system too. I need something that will give me control of the boost level in each gear. That will get me away from blowing away the tires going into second. The intercooler tank is another thing. A larger water capacity.
Updates on your project?
You would see a decient gain at 25-28 psi (being you didnt want to push the boost) with that back pressure. If you have intensions of going alot faster then you could upgrade to something like we discussed. As far as my project i'm still waiting on the ignition system. Hopefully I'll have some thing this week. I've decided to go to the dyno to test before heading back to the track. I'll get some tuning done while I'm there and make sure everything is ok. I'll also look to see where the cam makes its peak power to see where I need to shift it.
I finished studying the datalog more carefully and found that at the top of third where I took the bp reading I was getting an average of 24 psi boost (255 kPa with my equipment), even with the controller set at 22. I still have the stiffer spring package in the wastegate and though I have the adjuster backed almost completely out, I think the wastegate was still a little too tight for a 22 psi boost level. The advertised minimum boost level for the spring package I was using for that run is 166 kPa above atmospheric (266 kPa).
With a bp of 38 psi, that puts the ratio at 1.583. What do you guys think? If a realistic target is 1.5, that doesn't seem too far off to me.
With a bp of 38 psi, that puts the ratio at 1.583. What do you guys think? If a realistic target is 1.5, that doesn't seem too far off to me.
The latest video is in. The first two runs were on Saturday at 30 psi boost. You can hear the tire chatter through second gear. On Sunday I lowered the boost level and that took care of the tire chatter problem.
YouTube - DRW/Buick Alky V6 finding the limits
YouTube - DRW/Buick Alky V6 finding the limits
So Lazaris. With the newly figured 1.58 bp I have, what kind of improvement in bp and performance would you expect to see if I went with your suggestions on the turbine wheel and housing? With a 1.58 bp, do you think it would still be worth it to change it still? Is it realistic to expect say a 1.3 ratio? What kind of extraordinarily low bp readings have you witnessed or heard of, and what were the situations or configurations? I'm eager to read your response. Thanks for your help.
I would say going to a S trim wheel you will see about 40-50 hp gain, which at your power level 2-2.5 mph?? Could be worth more with higher boost. You didnt see what you were in the 30 psi range. You ran quite a few pass at that boost ? Thats where you originally were saying you were dropping boost. Thats why I suspected you were having high BP. If its worth it or not is up to you. It depends on how fast you want to go. At 25 psi I was at 1.2:1. This was with the configuration I sent you.
A previous configuration or your new one?
What are you running for tire press Don? I've found I can run a little less when racing 1/8mi as opposed to high mph 1/4mi. 10 1/2psi (tubes) seems to be my sweet spot resulting in good hook and somewhat managable topend in the 1/8 with the M/T's.
Scott Wile
I've been using 9 1/4psi with tubes too. If I keep my launches mild and keep the boost down for a dependable 1-2 shift, I could try a bit more tire pressure and see what happens. Good point Scott.
New one.
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