Target A/Fs and
 

Having just lost 3mm rear seal again, I am wondering whether my target of 11.4 (0.78La) is rich enough at 1.2/1.3Bar, what would you guys be aiming for at this boost?

(add. info: run in 900 miles, 13B street port, M800, T51RKai, plugs 10s, FMIC, EWP, 550/1500cc's. Adv 15, Split 10, Inj duty 67/84% at blow. Running a 50/50 split of SU98 & C16)

Thanks in advance..
GAP

What's SU98?

Running 11.4:1 at 1.3bar on that octane shouldn't be an issue, especially with that advance and trail-split. You sure the pump isn't just starting to run out of steam or something?

B

SU98 = Something unleaded 98 octane ? :)

Did you try running even less advance , before you got to 15 deg , like say 5 deg , and then work your way up (or down ) from there.

SU98 = Super Unleaded. 98 RON fuel.

It's about as performance fuel as we get over here. :(

Dan

PS. Phil I think you would be better off asking this on AusRotary.com ;)

Was the first seal you lost a 3mm?..What brand of seal?
I lost a 3mm seal on the dyno as well, running way rich, and normal amounts of timing, on my motor the seal basically folded over in the groove... no detonation, the seal just let go....Max

SX pump delivers 56psi and my inj duties were not OT. Couple of PSI low on pressure? (sorry Ign Adv 14)
Having been on dyno using 2mm tips, 98 octane and 1.2Bar, single piece 3mm's and higher octane I should've been ok.

Must have hit a limit somewhere, couldve been unlucky on seal?...

I know once that T51R gets into its stride it's awesome, that performance is very addictive. (The Rotary Reaper strikes, damn..)

P

Max - seal just lets go with no det... Not sure if I could tell at 7.6Krpm, as in my case - it was "one good fireworx out the back and the Brrrr of one rotor city".

Re: Target A/Fs and
 

I would run that AF in conjunction with water injection.

On fuel only I would recommend 10.8:1 @ minimum on that turbo/engine set up, just to keep everything "cool" Stop your seals turning into bananas :)

11.4 is border line and you are leaving no room for error in either the testing equipment or the fuel supply (delivery rate and quality). Just another opinion for you..... I would run it richer :D

Oh yeah on the timing I run 12 deg advance with 8 deg split on similar boosted engine with blended street fuel. With B11EGV or B10EGV plugs. Anyway good luck with it and tell us how you go.

Rice,
That clarifies a lot of things for me. I was led to believe 11.4:1 was safe enough, 10.8:1 does make sense. I could see the EGTs would ramp down and very possibly provide some much needed reliability (The Adv/Split values figure well...)

Damn, a spot of 11.7:1 is definite toast then!

I will get dowells & WI on this engine and be back with the results soon.

Thank-you..

Phil

The SX fuel pump is your problem. The SX pumps are not very good above 50 psi with 55psi being the max they will flow for any decent power. I used those pumps back in the early days and they all had the same problems. I'll say 400 rwhp as being the safe limit for it. The flow rate on the pump drops very quickly above 45 psi making it not applicable in boosted enviroments. Plus they suffer from over-heating issues where the pump would start to cavitate and the pressure would drop and in most cases stop pumping all together.

Listen to this advice :D I am no expert in this particular pump but it sounds like this is your major problem by far !!!!

A very quick spike (lean) as cause by an inadequate pump will kill it for sure, I know on my set up when I pushed the limits of the pump I ran (not SX) I could see a gentle tapper off in the AFR that could not be fixed in the fuel map.

It would be a shame if an inadequate pump or fuel system is costing you engines, best check it out and re engineer the system so it is of ample capacity for what you want to do ;)

i have a SX in my FD so far no problems....even when i was running 20psi tuning it..... held 15psi fine on the dyno when it made 459rwhp pull. i'm still thinking about changing to bosch motorsports pumps because i don't want to chance anything

Would have to agree w/Crispeed......

Ran a SX fuel pump for awhile (street-driven ~500rwh TurboII).......but had to lower static fuel pressure for it to maintain flow under boost.....@ 40psi static, pressure would take a dive @ ~20psi boost at higher rpms.....
I finally replaced when on the dyno I saw pressure drop to ~25psi under load !!!!!!!!!

The worst part.......if you wanted the pump rebuilt/serviced they had a loaner program while your pump was getting serviced which says alot of their reliability.
For turbo rotaries I would stay away from them.......

GAP:
17-18 psi w/15 degree advance is ok w/ 50/50 of 98 and C16 but next time drop it to 12 degrees and work your way up......split from 8 to 12 is also ok.....on the dyno your motor will tell you which is happier with.
As far as A/F's....I agree w/Rice racing....high 10's to keeps things a bit cooler......11.0-11.2 A/F my limit.

What 3mm seals are you using??? Hurleys??
What #'s were cranking at those levels??

Good Luck...

I've never been overly confident about the SX pump, also have intank Bosch up to a fuel catch tank helps I believe. Base @40psi, max tad low @55 (have seen dip @55-51-53). Don't want to see 25psi at full chat (eek!). Ok, rethink, Dual Bosch pump + intank pickup will surely do the job?.

I was running 3mm steel 2pc - not Hurleys, Mazda I think. Did find 2mm steels seal better, power delivery 500rpm earlier than 3mms on dyno.

Jury out whether I go steel 2mm or 3mm steels or plump up cash again and do 3mm Ianetti's (v.likely) - will decide when engine is split, check plates, housing & hope T51R survived..

Sound info - much appreciated

PS: Dyno'd 445rwhp@1.2Bar - 2mm seals/98RON
(T51Kai starts to perfom well at 1.2Bar)

You also got to maintain fuel pressure under boost. Minimum requirement is at least 1:1 or 1psi of fuel pressure to every 1 psi of boost pressure. So if you got 40 psi base fuel pressure at 0" inches then at 20 psi of boost pressure you should have at minimum 60 psi of fuel pressure.

I run 55 base psi with my Aeromotive 1000HP pump. No problems yet.

I am doing the same thing, except that I have a Bosch 044 pump in-tank feeding the in-line A1000.
~John