Calling all the "turbo" guru's guestions on ECU
08-30-2007, 03:02 PM
#1
AudiWorld Senior Member
Thread Starter
Join Date: Jul 2002
Posts: 1,571
Likes: 0
Received 0 Likes
on
0 Posts
Calling all the "turbo" guru's guestions on ECU
OK, let's get one thing straight, this car is being put together for the GRM 2007 Challenge in less than 5 weeks, so keep that in mind. Also, it only needs to run for a short period under boosted conditions for now.
What I want to know is if I can just change the manifolds and add the turbo and fuel dizzy without changing my ECU? It is my understanding that the ECU in the early turbos basically only controls timing and doesn't contribute to fuel enrichment or am I confused here?
I only need it for a little extra during the autocross phase of the challenge. Or would I be better off just putting in my NG with a 272 cam and the 5-3-1 exhaust?
I've compiled a nitrous system for the drag phase but nitrous isn't allowed in the autoX so I'm desparate for a little more uuuummmmphh there.
This all happening to my 87 4KQ
What I want to know is if I can just change the manifolds and add the turbo and fuel dizzy without changing my ECU? It is my understanding that the ECU in the early turbos basically only controls timing and doesn't contribute to fuel enrichment or am I confused here?
I only need it for a little extra during the autocross phase of the challenge. Or would I be better off just putting in my NG with a 272 cam and the 5-3-1 exhaust?
I've compiled a nitrous system for the drag phase but nitrous isn't allowed in the autoX so I'm desparate for a little more uuuummmmphh there.
This all happening to my 87 4KQ
08-30-2007, 03:08 PM
#2
AudiWorld Super User
A shot in the dark
In theory I dont see a problem, but I dont know. With the ECU not knowing you are boosting, it wont be able to compensate for the additional fuel that you will need, so your boost will be limited to around 5-6psi, I THINK. That makes sense to me, but Im probably wrong.
If you wanted to run those boost levels you could try, but keep in mind the wastegate is gonna have to go where the battery tray is!
If you wanted to run those boost levels you could try, but keep in mind the wastegate is gonna have to go where the battery tray is!
08-30-2007, 03:55 PM
#3
AudiWorld Senior Member
Thread Starter
Join Date: Jul 2002
Posts: 1,571
Likes: 0
Received 0 Likes
on
0 Posts
Re: A shot in the dark
Thanx, Mikey, for the positive support.
As for fuel enrichment, I'm hooking the nitrous up to a boost switch so it fires during boost, not sure of the value to start the nitrous but I was thinking around 5 lbs turbo boost.
This means during the autoX when the bottle has to be removed if I arm the system just the fuel ( wet system ) will flow through the nozzle, thereby enriching the boosted charge.
Maybe??? Crazy???
As for fuel enrichment, I'm hooking the nitrous up to a boost switch so it fires during boost, not sure of the value to start the nitrous but I was thinking around 5 lbs turbo boost.
This means during the autoX when the bottle has to be removed if I arm the system just the fuel ( wet system ) will flow through the nozzle, thereby enriching the boosted charge.
Maybe??? Crazy???
08-31-2007, 05:26 AM
#4
AudiWorld Super User
Join Date: Aug 2004
Posts: 3,535
Likes: 0
Received 0 Likes
on
0 Posts
"Kind of" ok to do..
Remembering how CIS works, and if you are talking about the Stock JT ecu (Maybe specify what ECU you are thinking of using?):
CIS measures air FLOW past the flap. So as long as you don't run more air past the flap than it was designed for, you should be ok.
What *are* you talking about, you ask?
Well.. nothing says you can be running boost in the midrange rpm level. You'll be getting more midrange torque, (probably opening the metering flap more than you would have before boosting), but still not hitting the limit of the flap travel. So will be Ok.
I suspect that you'll only run into that limit at higer revs AND lots of boost. As long as you don't have those two combinations at the same tiem, you sholdn't have a problem. Even then, I suspect there is a little headroom to play with! :-)
Suggestions:
Hook up you meter to the potentiometer output on the flap (JT fuel metering unit. Potentiometer output that goes to the stock JT ECU).
That way you can get a voltage measurement of the actual flap movememt. WIth the motor off, but the ign on, take the boot off, and pull the flap all the way up, and see what the voltage is on the pot. Maybe measure again with the flap down jsut a little bit too (Say ~90% open).
Now put everythign together agin. Because you can connct the meter to the pot, you have a way of knowing where the flap is, when the motor is running.
Another good idea would be to install an 02 sensor gauge, so you know when you run out of fuel, and are heading towards lean. Don't want that, under boost!
-Stock JT distributor does vacuum advance. Maybe check it it will do 'boost retard', or if there is a mechanical reason it won't? If not , you may want to back off the timing a bit too..
If you are talking about the early urq ecu (mac02):
Yes, only does timing. (whereas the JT ECU does not. Jt timing is all done with the distributor)
But..
The urq ECU needs the two flywheel sensors and the flywheel pin, so maybe back to just boosting the JT motor as is?
Oh... The quandry of it all!
Good luck, whatever way you end up doing it!
CIS measures air FLOW past the flap. So as long as you don't run more air past the flap than it was designed for, you should be ok.
What *are* you talking about, you ask?
Well.. nothing says you can be running boost in the midrange rpm level. You'll be getting more midrange torque, (probably opening the metering flap more than you would have before boosting), but still not hitting the limit of the flap travel. So will be Ok.
I suspect that you'll only run into that limit at higer revs AND lots of boost. As long as you don't have those two combinations at the same tiem, you sholdn't have a problem. Even then, I suspect there is a little headroom to play with! :-)
Suggestions:
Hook up you meter to the potentiometer output on the flap (JT fuel metering unit. Potentiometer output that goes to the stock JT ECU).
That way you can get a voltage measurement of the actual flap movememt. WIth the motor off, but the ign on, take the boot off, and pull the flap all the way up, and see what the voltage is on the pot. Maybe measure again with the flap down jsut a little bit too (Say ~90% open).
Now put everythign together agin. Because you can connct the meter to the pot, you have a way of knowing where the flap is, when the motor is running.
Another good idea would be to install an 02 sensor gauge, so you know when you run out of fuel, and are heading towards lean. Don't want that, under boost!
-Stock JT distributor does vacuum advance. Maybe check it it will do 'boost retard', or if there is a mechanical reason it won't? If not , you may want to back off the timing a bit too..
If you are talking about the early urq ecu (mac02):
Yes, only does timing. (whereas the JT ECU does not. Jt timing is all done with the distributor)
But..
The urq ECU needs the two flywheel sensors and the flywheel pin, so maybe back to just boosting the JT motor as is?
Oh... The quandry of it all!
Good luck, whatever way you end up doing it!
08-31-2007, 09:02 AM
#7
AudiWorld Super User
Join Date: Aug 2004
Posts: 3,535
Likes: 0
Received 0 Likes
on
0 Posts
Direct line to brain?
Noo...
Can't do that. But you could email me, and I'll send you the phone number..
Much easier to help out while on the phone!
:-)
Anyway, did I make sense? I wan't sure which ECU you were thinking of using, the urq one, or the JT one, so kind of hard to answer.
Can't do that. But you could email me, and I'll send you the phone number..
Much easier to help out while on the phone!
:-)
Anyway, did I make sense? I wan't sure which ECU you were thinking of using, the urq one, or the JT one, so kind of hard to answer.
Trending Topics
08-31-2007, 09:50 AM
#8
AudiWorld Super User
Agreed!!!
Frank has helped me out 124 times over the phone (well not really, but it feels that way).
He was responsible for getting the 4ktq to fire up too
.
Sucks we all only get to hang out once a year.
He was responsible for getting the 4ktq to fire up too
.Sucks we all only get to hang out once a year.
09-03-2007, 02:48 PM
#9
AudiWorld Member
Join Date: Apr 2005
Posts: 468
Likes: 0
Received 0 Likes
on
0 Posts
I was able to run 6-7psi on 91oct with stock timing on stock KX CIS...
See my video on Streetfire.net...
I think you'd be pretty happy with 7psi for AutoX. =)<ul><li><a href="http://videos.streetfire.net/video/8b212710-5cb9-4059-925f-98730076bbe4.htm">http://videos.streetfire.net/video/8b212710-5cb9-4059-925f-98730076bbe4.htm</a</li></ul>
I think you'd be pretty happy with 7psi for AutoX. =)<ul><li><a href="http://videos.streetfire.net/video/8b212710-5cb9-4059-925f-98730076bbe4.htm">http://videos.streetfire.net/video/8b212710-5cb9-4059-925f-98730076bbe4.htm</a</li></ul>
09-04-2007, 05:34 AM
#10
AudiWorld Super User
Join Date: Aug 2004
Posts: 3,535
Likes: 0
Received 0 Likes
on
0 Posts
Another idea..Programmable boost controller?
If you can get your hands on a programmable boost controller (HKS or whatever):
set it up for as much boost as you can get 'low down', going for increased mid range torque, but program it to drop of boost near the top so you don't go past what you can fuel with the stock Cis.
Effectivly, sort of giving you a flat torque curve all across the rpm range.
Turbo brings up the torque at low revs, and drops off boost as the motor naturaly comes 'on stream' as the revs rise.
set it up for as much boost as you can get 'low down', going for increased mid range torque, but program it to drop of boost near the top so you don't go past what you can fuel with the stock Cis.
Effectivly, sort of giving you a flat torque curve all across the rpm range.
Turbo brings up the torque at low revs, and drops off boost as the motor naturaly comes 'on stream' as the revs rise.