3SGE Throttle Body Conversion
SPYDER - 20/12/14 at 08:17 PM
So I have finally bitten the bullet and fitted throttle bodies to my 3SGE engined Spyder Silverstone.
They are GSXR750 42mm jobbies, respaced and mounted on a custom manifold.
The car was previously on Mikuni Solex 40's with 36mm chokes and had been dynoed by Peter Burgess
at 176 hp. It has coil-on-plug ignition using Hayabusa stick coils controlled by Megasquirt ecu with four spark outputs.
Fitment was relatively straightforward, including a front mounted swirl pot fed by the existing LP pump.
It started virtually straight-away using the software generated VE map. A few tuning sessions using the amazing VE AnalyzeLive software included
inTunerStudio got the map even closer but revealed a low tickover pulse width of 1.7ms.
This makes it difficult to accurately tune so I have upgraded to the latest HR11d high resolution code which has solved the problem.
The software upgrade was suggested by Brian Holzbach at EFI Analytics, the makers of TunerStudio.
I've been out again this afternoon to further enhance the VE map and the car is going like stink. Its amazing. Like a different car.
Only the acceleration parameters need sorting out now.
Once I'm happy its back on the rollers for a comparison figure and maybe final tuning of the spark map.
I'm anticipating something close to 200 hp and much stronger midrange torque, a commodity which the 3SGE isn't short of in the first
place.
Thanks to Chris and Eldon for help along the way.
Nickp - 21/12/14 at 09:01 AM
Nice work, the 3SGE is a cracking motor. I put a late one into an early MR2 and that went really well and loved to rev 
bombero - 21/12/14 at 12:42 PM
Out of interest, why did you choose to mount your bodies so far from the head? Installs tend to mount closer to the head and fit longer trumpets. This
would allow the fuel/air mixture to immediately enter the cylinder. Just wondering if this was a conscious decision...?
SPYDER - 21/12/14 at 03:26 PM
quote:
Originally posted by bombero
Out of interest, why did you choose to mount your bodies so far from the head? Installs tend to mount closer to the head and fit longer trumpets. This
would allow the fuel/air mixture to immediately enter the cylinder. Just wondering if this was a conscious decision...?
I'm not using the GSXR injectors. They are blanked off. I'm using the standard Toyota injectors which are mounted in the head. According to
the Jenvey website the best position for power is further from the head. Putting them closer to the valve is better for low speed running and
emissions. I chose to put my faith in Mr. Toyota and use the standard injectors in the standard position.
I've done some more VE table tuning today and I can report that the car is going like stink!
r1_pete - 21/12/14 at 07:41 PM
Nice job...
Good to hear you're having success with the layout, its very similar to the setup I'm going for on my E Type - Stock XJ6 EFI injector
position, with injectors spraying onto the back of the valve, then quite long runners to the butterflies, trumpets and a sausage filter.
EFI Trial Fit 2
SPYDER - 21/12/14 at 09:22 PM
What ECU are you going to use? You'll have fun balancing six butterflies!
bombero - 21/12/14 at 09:30 PM
quote:
Originally posted by SPYDER
quote:
Originally posted by bombero
Out of interest, why did you choose to mount your bodies so far from the head? Installs tend to mount closer to the head and fit longer trumpets. This
would allow the fuel/air mixture to immediately enter the cylinder. Just wondering if this was a conscious decision...?
I'm not using the GSXR injectors. They are blanked off. I'm using the standard Toyota injectors which are mounted in the head. According to
the Jenvey website the best position for power is further from the head. Putting them closer to the valve is better for low speed running and
emissions. I chose to put my faith in Mr. Toyota and use the standard injectors in the standard position.
I've done some more VE table tuning today and I can report that the car is going like stink!
Good into - cheers!
r1_pete - 22/12/14 at 09:48 AM
quote:
Originally posted by SPYDER
What ECU are you going to use? You'll have fun balancing six butterflies!
I'm using an MS2 from ExtraEFI...
The butterflies are two banks of 3 from Triumph Sprints, they have air bleed screws for fine balancing, and the throttle stop operates against each 3,
I have a vac take off on each throttle, and an 6 gauge vac balancer. The rose jointed linkages will allow infinite adjustment between the two banks (I
hope) and prevent any lag.
chris-g - 22/12/14 at 03:40 PM
Thanks for the mention but it was you who did all the work. I am looking forward to a passenger ride ride now its all up and running.
SPYDER - 22/12/14 at 09:55 PM
You'll be amazed Chris. I've done a little more tweaking today. Fitted a fuel cooler and an extra throttle return spring, re-balanced
butterflies etc., etc. See you soon.
SPYDER - 18/1/15 at 06:29 PM
The car went on the rollers this week. Power was up from 176hp on carbs to 194hp on the throttle bodies. The extra oomph builds from 3000 revs upwards
with an extra 16-18 lb.ft. across the midrange. Result!
We were tweaking the ignition map when a hose blew and brought proceedings to a wet and steamy end.
I've also fitted a revised cam cover. Next thing is a nice ally filler cap.
Before...
After...
SPYDER - 24/1/15 at 06:25 PM
And here's the final touch. A filler cap made on Chris's lathe and miller. Thanks Chris.
