v8 Ford Throttle Body on 951 engine questions
07-04-2018, 02:03 AM
#1
Race Car
Thread Starter
v8 Ford Throttle Body on 951 engine questions
Hi,
Hoping you guys can help.
I have installed a TB from a v8 ford engine to the intake of a 951 but would like to see some photos of the modifications you guys have done to make it work.
I'm running a map sensor on the pipe before the TB.
Question: how do you route air into the intake for start up/idle if the butterfly is closed on start up/idle?
Thanks!
Hoping you guys can help.
I have installed a TB from a v8 ford engine to the intake of a 951 but would like to see some photos of the modifications you guys have done to make it work.
I'm running a map sensor on the pipe before the TB.
Question: how do you route air into the intake for start up/idle if the butterfly is closed on start up/idle?
Thanks!
07-04-2018, 09:32 AM
#2
Race Car
Thread Starter
https://rennlist.com/forums/944-turb...options-4.html
The above link shows what people are doing for mounting, but doesn't discuss my concern for intake air for engine running at zero throttle input. I know the air should be "filtered" for cleanliness & also measured by the MAP sensor for proper engine management. So I suspect if I run hoses after air filter then feed the intake in one of the 15mm tubes on the intake near the head, essentially bypassing the TB. I guess if I can find an oem Porsche diagram, it would give me a general idea of routing.
The above link shows what people are doing for mounting, but doesn't discuss my concern for intake air for engine running at zero throttle input. I know the air should be "filtered" for cleanliness & also measured by the MAP sensor for proper engine management. So I suspect if I run hoses after air filter then feed the intake in one of the 15mm tubes on the intake near the head, essentially bypassing the TB. I guess if I can find an oem Porsche diagram, it would give me a general idea of routing.
07-04-2018, 11:14 AM
#3
Rainman
Rennlist Member
Rennlist Member
Noah,
if you're running a MAP sensor it should be behind the throttle plate. "manifold absolute pressure".
on my VEMS i added a T to the vac line going to the FPR for my MAP sensor.
where the Porsche TB had a bypass screw the Ford TBs tend to have a small bleed hole drilled in the throttle plate.
although the idle valve really will take care of most of the idle issue.
if you're running a MAP sensor it should be behind the throttle plate. "manifold absolute pressure".
on my VEMS i added a T to the vac line going to the FPR for my MAP sensor.
where the Porsche TB had a bypass screw the Ford TBs tend to have a small bleed hole drilled in the throttle plate.
although the idle valve really will take care of most of the idle issue.
07-04-2018, 12:51 PM
#4
Rennlist Member
The factory setup has the idle valve taking filtered air from before the throttle body and dumping it downstream of the throttle body via one of the ports on the intake manifold.
Be aware that the factory 944 idle valve is a PWM type, it will require setup and tuning to get it to meet idle speed targets and etc. If you are interested in a simpler setup, some factory Ford idle valves were an "on/off" type that requires no setup. When the car is cold the ECU switches it on, sort of creating a controlled vacuum leak that gives a fast idle. When warm it turns off. Simple but effective.
This is the same idea as the early 944 style valve but that valve has no ECU input whatsoever. It just gets switched 12v and as it warms up the air bypass gets less and less.
Be aware that the factory 944 idle valve is a PWM type, it will require setup and tuning to get it to meet idle speed targets and etc. If you are interested in a simpler setup, some factory Ford idle valves were an "on/off" type that requires no setup. When the car is cold the ECU switches it on, sort of creating a controlled vacuum leak that gives a fast idle. When warm it turns off. Simple but effective.
This is the same idea as the early 944 style valve but that valve has no ECU input whatsoever. It just gets switched 12v and as it warms up the air bypass gets less and less.
07-05-2018, 02:04 AM
#6
Three Wheelin'
Noah,
if you're running a MAP sensor it should be behind the throttle plate. "manifold absolute pressure".
on my VEMS i added a T to the vac line going to the FPR for my MAP sensor.
where the Porsche TB had a bypass screw the Ford TBs tend to have a small bleed hole drilled in the throttle plate.
although the idle valve really will take care of most of the idle issue.
if you're running a MAP sensor it should be behind the throttle plate. "manifold absolute pressure".
on my VEMS i added a T to the vac line going to the FPR for my MAP sensor.
where the Porsche TB had a bypass screw the Ford TBs tend to have a small bleed hole drilled in the throttle plate.
although the idle valve really will take care of most of the idle issue.
The factory setup has the idle valve taking filtered air from before the throttle body and dumping it downstream of the throttle body via one of the ports on the intake manifold.
Be aware that the factory 944 idle valve is a PWM type, it will require setup and tuning to get it to meet idle speed targets and etc. If you are interested in a simpler setup, some factory Ford idle valves were an "on/off" type that requires no setup. When the car is cold the ECU switches it on, sort of creating a controlled vacuum leak that gives a fast idle. When warm it turns off. Simple but effective.
This is the same idea as the early 944 style valve but that valve has no ECU input whatsoever. It just gets switched 12v and as it warms up the air bypass gets less and less.
Be aware that the factory 944 idle valve is a PWM type, it will require setup and tuning to get it to meet idle speed targets and etc. If you are interested in a simpler setup, some factory Ford idle valves were an "on/off" type that requires no setup. When the car is cold the ECU switches it on, sort of creating a controlled vacuum leak that gives a fast idle. When warm it turns off. Simple but effective.
This is the same idea as the early 944 style valve but that valve has no ECU input whatsoever. It just gets switched 12v and as it warms up the air bypass gets less and less.
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07-08-2018, 01:23 PM
#8
Race Car
Thread Starter
The factory setup has the idle valve taking filtered air from before the throttle body and dumping it downstream of the throttle body via one of the ports on the intake manifold.
Be aware that the factory 944 idle valve is a PWM type, it will require setup and tuning to get it to meet idle speed targets and etc. If you are interested in a simpler setup, some factory Ford idle valves were an "on/off" type that requires no setup. When the car is cold the ECU switches it on, sort of creating a controlled vacuum leak that gives a fast idle. When warm it turns off. Simple but effective.
This is the same idea as the early 944 style valve but that valve has no ECU input whatsoever. It just gets switched 12v and as it warms up the air bypass gets less and less.
Be aware that the factory 944 idle valve is a PWM type, it will require setup and tuning to get it to meet idle speed targets and etc. If you are interested in a simpler setup, some factory Ford idle valves were an "on/off" type that requires no setup. When the car is cold the ECU switches it on, sort of creating a controlled vacuum leak that gives a fast idle. When warm it turns off. Simple but effective.
This is the same idea as the early 944 style valve but that valve has no ECU input whatsoever. It just gets switched 12v and as it warms up the air bypass gets less and less.
07-08-2018, 01:30 PM
#9
Race Car
Thread Starter
Noah,
if you're running a MAP sensor it should be behind the throttle plate. "manifold absolute pressure".
on my VEMS i added a T to the vac line going to the FPR for my MAP sensor.
where the Porsche TB had a bypass screw the Ford TBs tend to have a small bleed hole drilled in the throttle plate.
although the idle valve really will take care of most of the idle issue.
if you're running a MAP sensor it should be behind the throttle plate. "manifold absolute pressure".
on my VEMS i added a T to the vac line going to the FPR for my MAP sensor.
where the Porsche TB had a bypass screw the Ford TBs tend to have a small bleed hole drilled in the throttle plate.
although the idle valve really will take care of most of the idle issue.
I think part of my confusion comes from converting from the AFM to MAP. I must have been thinking of the AFM measuring air before the TB, but what you say makes sense. MAP on the manifold. ECM tells air valve "more or less" and all the while the MAP is reading and supplying values to the ecm. Gotcha buddy!
07-08-2018, 01:45 PM
#10
Race Car
Thread Starter
Ideally the MAP sensor should have a dedicated signal line to the intake manifold that is not shared with any other component. I would check with Laust Pedersen (he posts on this forum) to see if he has any vacuum manifolds left.
This is good information. I guess it all depends on what the original poster is doing for engine management----that would be good info to have!
This is good information. I guess it all depends on what the original poster is doing for engine management----that would be good info to have!
The product I'm installing on an otherwise stock 951 engine: http://www.sdsefi.com/ (My car is called "Wilson" or "Rough Life Wilson" and I usually have some type of build thread on this or the non model specific forum).
I did read on the instructions regarding the MAP sensor, if the ecm is getting rapidly fluctuating values, then install a reduced like a mig wire welding tip (.035") in the line as it helps stabilize.
07-08-2018, 03:37 PM
#11
Rennlist Member
I tee'd my map sensor into the FPR/fuel damper vac lines as well:
https://cimg6.ibsrv.net/gimg/rennlis...5c26932bac.jpg
On the stock TB there's a nipple right downstream of the throttle plate. I used a 3-way vacuum line fitting. One goes to the TB nipple, one goes to the MAP sensor, one goes under the manifold. That last one splits between the FPR/damper. Never had a problem.
The MAP sensor is mounted on the TB bracket where the auto transmission kickdown cable would go (obviously not present in a 5 speed car). Used a small piece of steel drilled to match the 2 bolt holes on the sensor with a hole drilled for the sensor's nipple. The nipple goes through the hole where the cable end would seat in the bracket.
https://cimg6.ibsrv.net/gimg/rennlis...5c26932bac.jpg
On the stock TB there's a nipple right downstream of the throttle plate. I used a 3-way vacuum line fitting. One goes to the TB nipple, one goes to the MAP sensor, one goes under the manifold. That last one splits between the FPR/damper. Never had a problem.
The MAP sensor is mounted on the TB bracket where the auto transmission kickdown cable would go (obviously not present in a 5 speed car). Used a small piece of steel drilled to match the 2 bolt holes on the sensor with a hole drilled for the sensor's nipple. The nipple goes through the hole where the cable end would seat in the bracket.
07-08-2018, 09:10 PM
#12
Three Wheelin'
I tee'd my map sensor into the FPR/fuel damper vac lines as well:
https://cimg6.ibsrv.net/gimg/rennlis...5c26932bac.jpg
On the stock TB there's a nipple right downstream of the throttle plate. I used a 3-way vacuum line fitting. One goes to the TB nipple, one goes to the MAP sensor, one goes under the manifold. That last one splits between the FPR/damper. Never had a problem.
The MAP sensor is mounted on the TB bracket where the auto transmission kickdown cable would go (obviously not present in a 5 speed car). Used a small piece of steel drilled to match the 2 bolt holes on the sensor with a hole drilled for the sensor's nipple. The nipple goes through the hole where the cable end would seat in the bracket.
https://cimg6.ibsrv.net/gimg/rennlis...5c26932bac.jpg
On the stock TB there's a nipple right downstream of the throttle plate. I used a 3-way vacuum line fitting. One goes to the TB nipple, one goes to the MAP sensor, one goes under the manifold. That last one splits between the FPR/damper. Never had a problem.
The MAP sensor is mounted on the TB bracket where the auto transmission kickdown cable would go (obviously not present in a 5 speed car). Used a small piece of steel drilled to match the 2 bolt holes on the sensor with a hole drilled for the sensor's nipple. The nipple goes through the hole where the cable end would seat in the bracket.
That looks like a good solution for a NA 944, nice short run to the MAP sensor. The 951 engine bay is much more cramped, and the ideal place to install an external MAP sensor is on the firewall; therefore many people simply tee into the existing vacuum lines back there (my VEMS ECU has an internal MAP sensor, so I simply plugged the KLR line into that). The problem is, the stock 951 already has a long daisy chain of devices (including the bypass/"blow-off" valve) which tap into the same port on the manifold. The optimal solution is to have a dedicated port for each device, which ensures a strong signal and rapid response . Plus it makes checking for vacuum/boost leaks much, much easier!
Years' worth of discussion and conjecture about the subject can be found here:
https://rennlist.com/forums/944-turb...her-stuff.html
Last edited by Droops83; 07-08-2018 at 10:38 PM.