full throttle shift (stock ECU)

[karl]

so i got the full throttle shift setup running, but i think it needs a little bit of tweaking..

basically, what i did was this:

i had a crane cams ignition box lying around in my basement for a few years. i always thought it was blown, so i never bothered with it. on a whim, i tried installing it on the 2, and it wouldn't start the engine (i used the MSD tach adapter, i know that the ignitor needs the flyback voltage from the coil to trigger the IGF signal to the ECU, that wasn't the problem). turns out, it was supposed to be a plug and play unit (which have different wiring setups than the universal) and the guy i bought it from those years ago had cut off the plugs. so, i wired it up according to the new instructions and it fired right up.

anyway, the HI6S ignition has a stage rev limiter mode. you select a rev limit (3100+) and when 12v is applied to the yellow wire, the rev limit is active.

so, i tapped into the clutch switch (black wire gets pulled to ground when the clutch is pressed) and used that to ground a relay that then sends 12v to the ignition. so essentially, i have a rev limiter that's active only when the clutch is pressed. i also installed a switch on the dash to turn the system on and off.

basically, (right now at least) i can pin the throttle, and when i shift anywhere above 3300rpm, it cuts the ignition while i shift. it also works pretty well as a launch control, you just have to make damn sure you don't ride the clutch or it'll kick in

it works pretty well in 3-5th gears, but i'm noting some hesitation on the lower gears as the clutch comes out and the limiter turns off. i'm thinking it's just that the limiter is set pretty low at the moment. i wanted to start off slower, since i pretty much have to re-learn to drive the car this way. it's as smooth as regular shifting at this point, and i've noted the boost gauge only dropping about 5-6psi between shifts, as opposed to starting out again at 2-3 when the bov opens.

i'm considering having it cut fuel instead of ignition. i'm wondering if that would get rid of the bog i'm getting at the moment. anyone have any experience with full throttle shift setups?

[jdchmiel]

my DSM friend has no lift to shift set up in his eeprom chip in his factory ecu. I think his limiter is 6k with it engaged... you might find that higher RPM limit is better as what happens is the car drops rpm less between shifts and is much closer to the rpm the tranny wants to see for sliding into the next gear. this mod is great for a turbo car as there is no lag time with blowing off and rebuilding boost at each shift..

[karl]

i've also actually already designed a fuel cut box that would allow the use of WOT shifting on a stock car without having to install an aftermarket ignition as well. i'm thinking of making a few, but i don't know if anyone would be interested. judging by the replies i've gotten so far, probably not, hehe.

it would also replace the factory overboost fuel cut. so many people just disable it when it's there to save your engine. i find the factory cut, even when raised though, to be somewhat intrusive. i'd rather have a setup like the dsm's, where the car just hits a wall and won't boost any more than that. i'm talking to some electronics manufacturers about components right now, but it would be a simple add-on to the WOTshift box and would, IMO, be valuable engine protection..

[jdchmiel]

well throw that design out.
cut ignition not fuel. if you cut fuel you will be causing a lean condition in the on and off transitions and lean + full throttle full boost = BOOM

[karl]

hmm. the factory rev limiter cuts fuel at WOT and full boost if you hit ~7200rpm. i've hit it a few times and the engine seems no worse for wear? i also know of a few turbo hondas/dsm's that cut fuel instead of ignition.. i guess i could modify the design to simply "throw out" a few full fuel pulses, but make sure that any fuel pulses that DO go through in cut mode are full pulse widths..

of course, i could more easily do that with the ignition too.. even the stock ignition and its ghey IGF signal

[karl]

i had a chance to try it with the rev limiter raised to 4500 yesterday and all i can say is holy ****. the thing just comes alive, i push the clutch in as quick as i can, slight crackle out the exhaust, off the clutch as quick as i can and i'm on my way.

there's still a slight (1/2 second) pause as the limiter comes off, but i think this could be due to my wiring. i'm using a standard bosch automotive relay that's grounded off the clutch switch to send 12V to the digital input of the HI6S. the relay has a switching time of about 500mS, so i soldered up a solid state relay using a 2N3393 NPN transistor to take its place. the transistor has a switching time around 5uS, so it's about 100,000x faster than the relay.

[karl]

ok, it was my driving causing the problem, not the electronics i just wasn't getting my foot all the way off the clutch fast enough. the system works awesome!!!!!