• The site migration is complete! Hopefully everything transferred properly from the multiple decades old software we were using before. If you notice any issues please let me know, thanks! Also, I'm still working on things like chatbox, etc so hopefully those will be working in the next week or two.

Twin engine GTP project progress thread

penright said:
Do not these torque converters have a clutch? Seems like one of the comments in the thread for the turbo project car, had a great link to transmission description. If I remember right, the PCM commands (don't remember the conditions) the trans and fluid is applied though the input shaft to the converter and it locks a clutch. Would this not be the same here? Could you turn that off on just the rear engine? How do AWD allow differential(ing)?

Again, just thinking out loud.
Click to expand...

when the engine is not running the pump is not pumping fluid so no circuts get any fluid to lock or unlock the clutch which doesn't matter since none of the other clutch is engaged. but the differential and the output drive will still be turning at which point you need a pump to push fluid through the system and lubricate it.
as long as you don't have the f****** shifter in park you're good at that point lol
 
Last edited:


Turbocharged400sbc said:
for the "idle" trans we use a flat towing trans circulation pump to keep the guts of the rear trans wet while in neutral with the engine off.
Click to expand...
We were planning on doing this if we were to street drive a lot. Right now what I do is leave the engine running in neutral but I never go far without both engines running. The rear engine does not have heat problems at all. it runs 190F steady in 80F weather. I can leave it running. The front engine has a lot of strain if it's the only running engine even for cruising. It's best to leave both running it runs better that way although a little harder on fuel.

for short distances after being recently started and shutoff he should be fine since its mostly a racecar.

the Tq converters will stall as much as they need (slip) to equalize the load depending on the traction/load, that the beauty of a viscous tq multiplying drive. when launching the rear see's everything (one reason our 25.3 chassis is using 4x4 LCA hardware/heims and extra bracing)

so yer probably right the 1-2 did it in. but keep in mind that 400ftlbs is plenty to break a stock IS when the shock load can have the converter multiplying that up to 1000+ for a split second. plus without the rear driving a SC yer already 50+hp more than the front engine just from the crank not spinning it.
Click to expand...

I will be forcing the trans in 2nd gear for launches. With more boost it will launch just as hard. When the front engine will be turbo, it will also leave in 2nd gear.

you may want to look into the 3.71fdr 80e though i dont think it will clear your unibody rails, thats just a mallet and a few licks away....

looking good guys.

kinda make me pissed we havent gotten more done on the 442 in the 14 year build/rebuild/rebuild lol
Click to expand...

Thanks ! Yes it will probably motivate you to do a last push to complete your own crazy project.
AS for the 4T80E it's a heavy pig, and the weight is already an issue. I am genuinely worried about being able to slow down without a parachute. It will be hard to slow down from a 145 mph trap speed at 4500lbs + race weight on stock size GTP brakes. I'd love to go bigger but I won't be able to run my slicks up front.

Also how much wider is it from the block to the body ? I only have 2 inches between the trans and the rear frame rails or 1 inch between the factory trans mount gusset to the rail.
 
darkhorizon said:
Pull tons of power at the 1 2 shift.. way easier than dealing with a second gear start or anything. On my drag car I run a touch of fuel cut on the 1 2 shift.
Click to expand...
I regret not leaving some form of torque management now. I knew I'd be looking into a built trans when the power went up but not at this low power level.
We are swapping the trans now from the parts car to the twin engine. And I will do 2nd gear start and see if it can last in those conditions. If it doesn't the project will be on hold till I get a built trans.
 
TwinV6GTP said:
We were planning on doing this if we were to street drive a lot. Right now what I do is leave the engine running in neutral but I never go far without both engines running. The rear engine does not have heat problems at all. it runs 190F steady in 80F weather. I can leave it running. The front engine has a lot of strain if it's the only running engine even for cruising. It's best to leave both running it runs better that way although a little harder on fuel.
Click to expand...
We are likely switching to the rear as the primary powerplant... its built for low/mid range tq, so it is far more suited to moving the heavy car by itself than just the front engine which is set up for mid range and top end power
TwinV6GTP said:
Thanks ! Yes it will probably motivate you to do a last push to complete your own crazy project.
AS for the 4T80E it's a heavy pig, and the weight is already an issue. I am genuinely worried about being able to slow down without a parachute. It will be hard to slow down from a 145 mph trap speed at 4500lbs + race weight on stock size GTP brakes. I'd love to go bigger but I won't be able to run my slicks up front.

Also how much wider is it from the block to the body ? I only have 2 inches between the trans and the rear frame rails or 1 inch between the factory trans mount gusset to the rail.
Click to expand...
while the 4t80e weighs 65 pounds more it is far stronger in every way Plus you should probably be tuning your engine braking tables to help at the track.

you could probably fit in there just using a hammer
 
Turbocharged400sbc said:
when the engine is not running the pump is not pumping fluid so no circuts get any fluid to lock or unlock the clutch
Click to expand...
I hear you. I speaking to the one theory of why the chain broke or better said why it was ruled out as a possibility(front and back trans : gear ratio/actually selected gear at the time/size of tires/engines RPM). It was ruled out as a possibility because of torque converter slippage. My question was do they not "lock up" when commanded to? How does this effect synchronising the front/back? May still not have any thing to do with it, just asking.



Turbocharged400sbc said:
shifter in park you're good at that point lol
Click to expand...
Ouch. You could lay a long set of "burnout appearing" marks dragging the rear. Or at least as long as the trany held.
 
Turbocharged400sbc said:
We are likely switching to the rear as the primary powerplant... its built for low/mid range tq, so it is far more suited to moving the heavy car by itself than just the front engine which is set up for mid range and top end power

while the 4t80e weighs 65 pounds more it is far stronger in every way Plus you should probably be tuning your engine braking tables to help at the track.

you could probably fit in there just using a hammer
Click to expand...
Where is that table in HP tuners ?
Is it the downshift table at zero throttle position ?

What's needed on the electronic side to make it work ?
I read that you need to grind the block a little and make custom bracket for the K-frame which isn't hard to do.
 


Hpt sucks
Dhp/tiny/uv fer tha win

you need to do an inverter on one of the shift solenoids but Dave Norris at triple edge figured out the settings to use with the tech2 so that you do not need to invert the shift solenoid signal
 
Turbocharged400sbc said:
so did you figure out a hand or left foot throttle yet?
Click to expand...
Just added another throttle cable to the same pedal.

I can throttle the rear engine independantly for spooling up the turbo. I can't throttle the front engine independantly.
So I can shut the rear engine off and leave in Neutral while I do my front burnout, then I can do a rear burnout with the front engine still running.

 


Jomamma said:
At least there aren't any holes in the bumper....
Click to expand...

speed holes... they were made to break from 11.0 to 10.9 but it didn't work lol on the parts car.

AS for the spoiler, it was removed to make space for vents but I have figured out something cool with the spoiler on, you guys will see soon.
 


the rear engine bay air exits just fine out under the rear bumper into the low pressure area behind the car. on top of the trunk will not be nearly as good of an air flow path
 
Turbocharged400sbc said:
the rear engine bay air exits just fine out under the rear bumper into the low pressure area behind the car. on top of the trunk will not be nearly as good of an air flow path
Click to expand...

That's where the radiator was going to go, in an angle with the fans blowing air through the trunk but we have it in front of the engine right now, with the airflow under the car, it stays pretty cool.
 
keep it there you dont want that weight at the back of the vehicle. our new chassis is goin to only have the fuel cell that's at the rear of the car...it looks like we might be able to do saddle fuel tanks in front of the rear engine with the new radiator set up...but the fallback is at the rear...away from the driver lol

your goin two want to try to keep as much of the weight towards the CoG.
 
Very cool. Glad to see it at this stage.
beer_cheers.gif
 
You must log in or register to reply here.
Back
Top