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turbo/EFI setup

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I have a 1990 GSXR 750L, currently set to run 14.7lbs Boost and lays a solid 200hp at the wheel. I managed to set a 750-M-BF record in Utah last summer with a 180mph qualifying run and 184 mph backup run on the intermediate 5mile course. Next time I’ll try for the long course and see what it can REALLY do!


Engine Management System - Megasquirt 2, V3.0 board operating MS2extra 3.4.2. I have a CANEGT module with 4 closed tip probes for 1-4cyl, 2 open tip probes mounted in special adapters to read pre and post oil cooler temps, and one mounted right after the turbo to show me turbo outlet temp readings. I’ve also got a turbo oil feed pressure sensor, a main oil gallery pressure sensor, and a fuel pressure sensor- I can only read one at a time ( out of analog inputs ). I’m using Speed density engine control and batch injection. 


Ignition system: stock VR sensor reading cranks speed via 24-2 trigger-wheel made by Arttu, output controlled by MS2 FET drivers —->triggering a Mitsubishi J702T ignitor(from a Mazda miata I believe), and I’ve been using an IGN4 wasted spark coil with regular ole wires and plugs, nothing fancy. Oh, and CR10 spark plugs with a slightly reduced gap.


Throttle bodies: k7/8 tb’s spaced in the middle and jammed in to the stock boots, with stock injectors. I’m using a staged injection setup- once I reach a high enough duty cycle on my primaries I transition to 50/50 between primaries and secondaries. Duty cycle at current power level is about 65%


Injector sizes: Primary and secondary are 225cc I believe. 


Std Coils or Pencil stick coils (type / part number / model) : IGN-4 wasted spark


Fuel pressure at pump: walbro pump but I can’t remember what it flows (255 I think)- I do remember that it had 30% excess fuel flow at a flow rate to give enough fuel for 300hp. Aeromotive FPR referencing port vacuum/boost.


I have an MS3x ready to plop in there with a BUNCH of additional sensors and hope to have this baby fine tuned and ready to race on the salt again in 2021..

Here are 2 dyno runs almost a year apart. They’re both in red ( sorry ) but the light red was last 2019, and darker red was a few months ago. Since my first trip I’ve tried to flatten that torque up top, and my little tweaks worked, but boost control is not my strong point so there are some fluctuations



I was a happy camper after I tortured it in bonneville.. 9 runs in total. My last 2 runs were wot for around 50 seconds! Thanks to a solid tuning platform, my AFR was solid at 11.5-11.7, and with all the other information I was able to collect I could run with confidence and focus on staying straight and upright. 


I owe a lot of what I was able to accomplish to a lot of you guys- by posting and sharing experiences online in places like this, I could learn and teach myself what to do ( and what not to do hahah). 

Thanks fellas

Oldskoolsuzukis kicks ass!


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  • 1 month later...

@mikeydthank you, but Suzuki takes the credit for building a solid motor! The motor is totally stock aside from heavy duty custom turbo pistons from WEISCO. 


If i I have any kind of aerodynamic aid, it will most definitely put me into another class. For now I chose to race in the open class to keep my build simple. 

A fellow I was privileged to meet on the salt and fellow Canadian ( Tom Mellor, google ‘Tom Mellor triumph’) has a VERY impressive aerodynamic fairing that was home Built and had propelled him into the 200mph club several times with naturally aspirated motors.. one year he rode his bike in 2 classes, one with and one with out the fairing. That fairing gave him a 40-50 mph speed difference. I think typical gains might be in the 20mph range with proper aero. The engine he was using when I met him was in the 1000cc class, and made a whopping 110-115hp, and his shake down run came in at 192mph!!!

One day I’ll take a chapter out of his book, and I’ll build a similar fairing. 

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