An interesting day on the dyno

[PZG302]

Well I had an interesting day on the dyno getting my motor finally set up for fuel with the computer.

 

Basic specs are:

• L28 stroker to L31
  
• N42 head - some tidy up of chambers and ports for flow
  
• Haltech F9 computer and L28 electronic dizzy
  
• L28 N42 cast turbo log maifold and standard injectors
  

 

After a few false starts due to not enough time and niggly things like throttle linkages not lining up with the new inlet manifold I finally got the old girl onto the dyno to get the fuel sorted with putting my old race head on the stroker bottom end.

 

Previously this motor ran a E88 head with standard 280ZX manifold and recorded a dyno figure of 142 rwhp on a dyno dynamics dyno in shootout mode with points dizzy and 125 rwhp on the dyno used by Powertorque engines up here in Brisbane with an electronic dizzy.

 

The rebuild of the car this year saw my old N42 go on the bottom end and a turbo log manifold with 63mm diameter single throttle body replacing the standard L28E manifold. Standard injecors are still being used as they can comfortably supply enough fuel.

 

As previously stated the throttle linkages were a drama. This is due to the runners on the new manifold being about 1/2 inch longer than the old manifold and only giving me about 1/4 throttle, not good for any motor.

 

A day or so of mucking around had the linkages adjusted correctly to give me full throttle.

 

Off to the workshop today for the final tune so I can have a play at Lakeside in a fortnight and then onto the Noosa Hillclimb in mid November.

 

More dramas, the motor is as the mechanic said - "breathing heavier than a peodophile at a wiggles concert", this maybe due to the fact that it was originally built with the crankcase breather blocked off and all breathing through the top end, or the bottom end needs a freshen up.

 

When revving hard under load the amount of smoke out of the catch can is not pretty. It looks like I will be up for a bottom end rebiuld in the new year :-\

 

The good news is that when geeting the fuel right I saw 131 rwhp at just under 5k and plenty of torque. 6hp more and 2k less I'm impressed.

 

Looks like this will motor would show an honest 150 or so if we did a power run, which would equate to about 160-165 rwhp on a dyno dynamics shootout run. Very happy about this especially as the torque curve will be as flat as before . I like my motors like me - fat and lazy 

 

Now I will be running its first event in three years at Noosa as the mechanic was not confident it will last a track day. This will be fun learning the car again, and the MX gets another flogging on the track :-\

 

Finding out a little more of the history of the motor tonight it looks like that it is overdue for a bottom end freshen up and while it could cope with the E88 head the much better N42 head is now causing the bottom end some grief. A fair bit more fuel has been added to the maps with the better flow.

 

Best get the spare blocks ready to be bought into service if this one is shot!!!

 

Jason, hope you're not going away over Christmas I can see a rebuild happening!!!!!

[Aaron Neubauer]

What cam are you running and are you still using AFM of an kind?

 

My engine build is basically along these lines so I'm quite interested!

[PZG302]

The cam I'm running is a Nissan motorsport 76 degree grind, don't have the specs here with me, but is an off the shelf grind.

 

I am still using an AFM, what I believe to be the standard one that was fitted to my inlet log, made a mistake in the first post, the casting number is N47 on the log. I believe it is a turbo log of some description and has a single throttle with the butterfly at 63mm in diameter.

 

The only modification to the AFM is to enable me to run the Haltech F9 computer that I have used since about 1994 with no problems.

 

If you're in Brisbane you're always welcome to wander around to have a look.