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EFI_LC's VR SS Commodore 5.0


EFI_LC

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  • 2 weeks later...
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Well I was lucky enough to get some Dyno time and a direct comparison to the exhaust change, what is evident is the limitation of the induction system, it hits peak power then flat-lines from 4600 to 5600rpm with only 2hp difference between.

 

What is clear though is a considerable gain through out the rev range from around 3300rpm, I have also changed where the car shifts, 1st changes to second at about 6000rpm instead of 5200 and this helps it drop back into the power range, I am still working on second gear change as I can manually shift at around 5800rpm. Also the shift speeds and slippage now needs some work, 1st shifts in about .7 second and 2nd a little longer which I could speed up a bit.

 

The ability to change the transmission as well as the engine means with any mod, I can make the transmission do what I want.

The next big one I want to do is in performance mode add slippage on launch (Launch control) which works similar to a high stall convertor by allowing the engine to rev higher which puts more power to the ground.

 

 

Anyway enough of my ramblings, here is the Dyno sheet with August runs, at around 4250 I am around 12hp and 10FtLb ahead and it holds the power and torque in the higher revs much longer. Twin 2.5" with no balance between them however the collectors are limited to 2.25" and may change next year sometime if I upgrade the extractors.

 

Approx. 270hp at the Flywheel which means I am about halfway there and about 1 second on the drag strip slower than where I plan to be.

 

Dyno-15-Nov-2013-small_zps4775ae5c.jpg

 

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Well this translated into another small step closer to the first hurdle I set, 100mph in the 1/4.

Could only manage 14.3@98 but I am slowly getting there. I know where a half second or more is but it will take a couple more mods, DYO drags tomorrow and I made another small mod to the airbox to help the flow as when the air left it went into a horrible bend which looks like it restricts it so I made it a straight from a spare piece I had in the garage and turning the airbox 180 and drilling a hole in the opposite end.

 

airboxmod_zpsbc155206.jpg

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A common mod on these things back in the mid 90's was to cut out a wide mouth (about four inches wide and about an inch high from memory) in the lower half of the airbox for it to draw additional air in because the factory airboxes were notoriously restrictive.

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A common mod on these things back in the mid 90's was to cut out a wide mouth (about four inches wide and about an inch high from memory) in the lower half of the airbox for it to draw additional air in because the factory airboxes were notoriously restrictive.

Thanks for that one k-trips, it was done prior to me getting it and that has been loosely partitioned to draw air from the front, I am going to try and insulate the box and all parts better as well as make the partition seal better so it can't suck hot air from the engine compartment. They painted it black of all colours.

 

I am also going to look at venting the bonnet to allow the heat to come out of the engine bay as when it sits the heat soaks into everything under the bonnet.

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  • 11 months later...

I have made some progress with the Carburettor and achieved 180kW at the wheels which is a 15kW and now it revs well over 6000.

 

I will give it another run at the drags on Sunday before making judgement though as after finding a vacuum leak and fixing it I reckon it will be running a bit rich.

I will pull the plugs out after a couple of runs to check how they are burning.

 

10536821_291365894390030_542255709365049

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Its a Pro Comp, so nothing special

 

I added a Carter Electric Fuel Pump today and a regulator and gauge, I was using a Fawcet style up to now as they are pretty good for stock Holden motors but may have been struggling up top.

 

I adjusted the float level as I had an issue where the adjustment was a bit low on the rear float.

I puled out the mains and replaced them with the standard jets but wasn't happy so went with an in between jet to try. The drive to the Drags tomorrow will make up my mind if it was the right choice.

 

Then I may have a tinker with the spark and may put into action the extended map to 6500rpm instead of 4800 to see if it will red it.

Initial drive feels more responsive down low but not up to where the Injection was but still pulls well over 4000rpm.

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  • 2 weeks later...

Hi Bart

I had mixed success, I slowly mad e some changes but was suffering from timing issues, I change to a new type of tune and went backwards, I had another problem which I wasn't sure of so stopped any further runs. When I got him I checked and sure enough I had broken the passenger side engine mount, it actually pulled one of the earth straps off. I had a bit of a talk to a mate and now have started again on a tune, Using 0 computer advance at 400 & 800rpm and 4.5 @ 1200 I can now start it with more static timing which it needs and have stopped the pre-ignition when turning it off.

 

I now have a slight stutter on the carb now when I use any more than 1/2 throttle off the line, I found I could stop this with advance timing before but was unable to find a balance which allowed the engine to wind over easy, idle and stop nicely.

Looks like I may need to adjust the carb before I try any further timing adjustments although I need to try and find the limit of how much timing I can run 400/800/1200rpm yet. I am learning and now I feel I am very close to finding the lower down tune.

 

It likes to idle around 1200rpm, this helps when putting it in 1st as it drops to 700-800rpm, anything lower than that causes the idle to be quite rough and I can't add timing to smooth it because of what i described above and the cam causes the engine to have less vacuum.

 

Sorry sr1600, I have a set of rotors buried in my back shed and will need to measure

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