Yellow Bullet Forums banner

81 - 90 of 90 Posts

·
Registered
Joined
·
16,411 Posts
Dave also has a converter that is ~1100rpm tighter...
How do you figure that? At 7 psi Dave was at 4300 rpm. Cam claims 3500 rpm at 10lbs boost.

Truth is it's hard to compare converters unless someone has data showing the initial stall with no boost. With no boost my converter stalls at 2800 or so.
 

·
Registered
Joined
·
23,817 Posts
Discussion Starter #82
How do you figure that? At 7 psi Dave was at 4300 rpm. Cam claims 3500 rpm at 10lbs boost.

Truth is it's hard to compare converters unless someone has data showing the initial stall with no boost. With no boost my converter stalls at 2800 or so.

Hes going by the PTC numbers . Fin angle , windows , ect

How long it takes to get up on the converter .
 

·
Registered
Joined
·
5,621 Posts
I think Dave has basically the same converter as I run, PTC 9.5 12-45 stator and mine has a mechanical diode plus is bolt together. I don't have any issues except slip is still 11% at 8100rpm at the 1/8th mile stripe. I think there is a new cover that is supposed to be 5% - 6% more efficient I should probably try. It snaps right up on the converter making 10psi in 1.2sec from going WOT on transbrake. Generally more than I can use without pulling a ton of power with timing. Hopefully the new Haltech Nexus system will give me a much wider array of control options. Hopefully they ship on Wednesday. Hope you find your issue Dave. Chasing stuff like that sucks, when it's not obvious as to what's wrong after teardown.
 

·
Registered
Joined
·
1,807 Posts
12-45 would be awefully tight for a 383 sbc imo

i have that on my 555 bbc thats 10:1, heads that flow 425 and when it was all motor, it would flash to 3600 from a roll. It definitely would be tighter than that on a sbc
 

·
Registered
Joined
·
23,817 Posts
Discussion Starter #85
I think Dave has basically the same converter as I run, PTC 9.5 12-45 stator and mine has a mechanical diode plus is bolt together. I don't have any issues except slip is still 11% at 8100rpm at the 1/8th mile stripe. I think there is a new cover that is supposed to be 5% - 6% more efficient I should probably try. It snaps right up on the converter making 10psi in 1.2sec from going WOT on transbrake. Generally more than I can use without pulling a ton of power with timing. Hopefully the new Haltech Nexus system will give me a much wider array of control options. Hopefully they ship on Wednesday. Hope you find your issue Dave. Chasing stuff like that sucks, when it's not obvious as to what's wrong after teardown.
Thanks . I didnt find anything out of the ordinary after tearing it down . If your talking about the valve train noise . I mean nothing !

Yea , I think you have the same converter . It had no issues with the other turbo . Once up on the converter , it was quick to 11psi on the brake .

It could also have a lot to do with the NA power . I have a 383 sbc with only 8.5:1 cr . When its ready for a total rebuild , I might change that with decking the block and or pistons . I cant remember exactly how far down in the hole they were , but the new block was never decked .
 

·
Registered
Joined
·
23,817 Posts
Discussion Starter #86
12-45 would be awefully tight for a 383 sbc imo

i have that on my 555 bbc thats 10:1, heads that flow 425 and when it was all motor, it would flash to 3600 from a roll. It definitely would be tighter than that on a sbc
Its tight for sure . You can snap the throttle and you dont get that instant wheel spin . But like I said , its also low compression .

It needs to be that tight though for towing . And being 4600 lbs with the power at the track . I think I still have 10% slip at 156mph 1/4 mile
 

·
Registered
Joined
·
1,101 Posts
What is the typical gains in efficiency from 1.32 to 1.58 on the 96?
depends on back pressure, for example, my tiny 308 was having some back pressure issues above 25+ psi with a Bullseye 83/96mm turbine (s400 chassis) 1.32 ar. Put a 1.58 and I picked up 2 tenths and a few mph at the same boost level. Went from going 8.24-8.26 to 8.07-8.08s @ 170.
 

·
Registered
Joined
·
838 Posts
depends on back pressure, for example, my tiny 308 was having some back pressure issues above 25+ psi with a Bullseye 83/96mm turbine (s400 chassis) 1.32 ar. Put a 1.58 and I picked up 2 tenths and a few mph at the same boost level. Went from going 8.24-8.26 to 8.07-8.08s @ 170.
Wow. Thanks for sharing.
 

·
Registered
Joined
·
3,443 Posts
That's why I gets tough making big power at a lower RPM when it comes to the converter


Sure, would be nice to run a 15-0 on Dave's... Get on the two step in spool instantly..... Wouldn't do jack s*** going down track tho... at the RPM range that engine wants to make power and his raceweight on top of it

It would literally just lay on the converter
 
81 - 90 of 90 Posts
Top