951 2.8 Stroker Tuning questions
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Joined: Mar 2005
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951 2.8 Stroker Tuning questions
I just completed my 2.8 stroker project and finally got a chance to start it up. I've tuned idle best I could and it still seems to be running pretty rough as if there's a air leak at the intake of some sort causing the idle to be very erratic. 900-1000. The reading on the WB also jumps from 14 to 14.7 at times. The problem seems to be worse after the car warms up. I also noticed the RPM isn't very stable if you try to maintain a constant RPM say 2k or 3k almost like it's missing slightly. On throttle reponse seems pretty good and under acceleration seems pretty good as well. I also noticed that having the connections to the idle stablizer on or off has no effect on the idle. Anyway I was hoping for some advice on troubleshooting intake leaks and rough idle problems. Is there a simple way to check for leaks by creating one and if nothing changes then there's a leak elsewhere or something like that?? Any advice is appreciated.
Thanks, Brent
P.S If any 951 owners need OEM parts from either WorldPac or IMC let me know, I worked out a good deal to get cost on everything.
Thanks, Brent
P.S If any 951 owners need OEM parts from either WorldPac or IMC let me know, I worked out a good deal to get cost on everything.
Drifting
Joined: Jun 2003
Posts: 2,101
Likes: 0
From: Taiwan
Hi Brent,
Firstly congrads on your project. Are you running custom chip ?
Did you change the NTC sensor. My 2.5 behaves exactly like yours.
I've trace the problem partly to the NTC sensor. The WB reading
will dither up & down. It will not just sit still. It's normal.
Firstly congrads on your project. Are you running custom chip ?
Did you change the NTC sensor. My 2.5 behaves exactly like yours.
I've trace the problem partly to the NTC sensor. The WB reading
will dither up & down. It will not just sit still. It's normal.
Racer
Joined: Feb 2005
Posts: 332
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From: UK
Although this will not be directly relevent to your car because no doubt these parts will have been scrapped. I did see these symptoms on a friends lux (rough idling and trouble sitting at steady RPM) when he had a small fracture in the rubber hose behind the AFM. So as an uneducated guess I'd say the air leak idea is likely to be correct and I'd check the system between AFM and manifolds.
p.s. you'll have to do a report on your cars performance when its all set up and finished because I'm also in the process of a 2.8 stroker conversion. So I'm very interested to hear results.
Ben
p.s. you'll have to do a report on your cars performance when its all set up and finished because I'm also in the process of a 2.8 stroker conversion. So I'm very interested to hear results.
Ben
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Joined: Mar 2005
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Are you running custom chip ?
I'm currently running Autothority Stage II chips until I can find out what my baseline should be and have some custom chips made.
Did you change the NTC sensor.
I replaced all the sensors (I should check it out just in case, the car does run a low richer cold though) and hoses except for the idle stablizer which I'll probably be replacing shortly.
What are you tuning your idle air/fuel with? Details please!
Mafterburner piggy back computer with Autothority stage II chips. Here are the current corrections in the fuel computer. FQS is set to 0, tried 2 as well.
10 -54
.30v -54
.50v -54
.70v -25
.90v +6
1.10v +23
1.30v +27
1.50v +26
1.70v +23
1.90v +30
2.10v +30
2.30v +30
2.50v +28
2.70v +20
p.s. you'll have to do a report on your cars performance when its all set up and finished because I'm also in the process of a 2.8 stroker conversion. So I'm very interested to hear results.
As soon as I get it running I'll let you know I'm going with Danno to have it tuned on a Dyno in two weeks if I can get running properly.
I'm currently running Autothority Stage II chips until I can find out what my baseline should be and have some custom chips made.
Did you change the NTC sensor.
I replaced all the sensors (I should check it out just in case, the car does run a low richer cold though) and hoses except for the idle stablizer which I'll probably be replacing shortly.
What are you tuning your idle air/fuel with? Details please!
Mafterburner piggy back computer with Autothority stage II chips. Here are the current corrections in the fuel computer. FQS is set to 0, tried 2 as well.
10 -54
.30v -54
.50v -54
.70v -25
.90v +6
1.10v +23
1.30v +27
1.50v +26
1.70v +23
1.90v +30
2.10v +30
2.30v +30
2.50v +28
2.70v +20
p.s. you'll have to do a report on your cars performance when its all set up and finished because I'm also in the process of a 2.8 stroker conversion. So I'm very interested to hear results.
As soon as I get it running I'll let you know I'm going with Danno to have it tuned on a Dyno in two weeks if I can get running properly.
Burning Brakes
Joined: Mar 2004
Posts: 837
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From: Seattle
You are a far more experienced mechanic than I am to undertake a project like that, so this is may be something you have already tried. Just in case, have you tried listening for it? I use a 3' piece of soft tubing with one end in my ear, move it around until you hear the sucking sound. Simple but it works.
Lou
Lou
Pro
Joined: Sep 2002
Posts: 554
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From: Montreal and Texas
Brent951. Take it from me, get some custom chips , from Vitesse. The timming values for the strocker 2.8L are not the same as the 2.5L. They are very touchy with regards to timming, and you can easily melt it down, if your timming is wrong.
Trending Topics
Pro
Joined: Nov 2003
Posts: 550
Likes: 10
From: Bay Area, CA
I agree. Get a chipset from Vitesse.
When I initially fired up the engine, I only used my Authority Stage II to idle and free rev to find leaks. I didn't put any load on the engine because the timing values are different for 2.8. (the longer stroke = longer TDC dwell time)..
With the Vitesse chips I broke in the 2.8 liter motor and passed a CA smog test.
Recently I swapped my hot side turbine (reduce lag) and removed the CAT. I need to do some more tuning, but so far I ran with a friend's 2.5 liter K-27/8 Turbo S (~300 whp) in 3rd gear. You all know about the nice torque hit in 3rd gear at 60... well I now pull 3 car lengths ahead of him when we both sream to the top of the gear. yee hah.
Steve
When I initially fired up the engine, I only used my Authority Stage II to idle and free rev to find leaks. I didn't put any load on the engine because the timing values are different for 2.8. (the longer stroke = longer TDC dwell time)..
With the Vitesse chips I broke in the 2.8 liter motor and passed a CA smog test.
Recently I swapped my hot side turbine (reduce lag) and removed the CAT. I need to do some more tuning, but so far I ran with a friend's 2.5 liter K-27/8 Turbo S (~300 whp) in 3rd gear. You all know about the nice torque hit in 3rd gear at 60... well I now pull 3 car lengths ahead of him when we both sream to the top of the gear. yee hah.
Steve
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Joe Kucinski
Rennlist Member
Joined: Oct 2003
Posts: 1,589
Likes: 1
From: Ontario, Canada
There's nothng wrong with Authority chips.
The real issue is what air flow metering device are you using; and what injector size.
The stock AFM and stock injectors are too small for a 2.8 L. unless quite low boost is run.
After this is addressed, then you seek out custom chips.
Also, if the timing is good for a 2.5L, it will definitely be safe for a 2.8L stroker.
Longer stroke = SHORTER TDC dwell time (needs more advance for max power)
The real issue is what air flow metering device are you using; and what injector size.
The stock AFM and stock injectors are too small for a 2.8 L. unless quite low boost is run.
After this is addressed, then you seek out custom chips.
Also, if the timing is good for a 2.5L, it will definitely be safe for a 2.8L stroker.
Longer stroke = SHORTER TDC dwell time (needs more advance for max power)
Thread Starter
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Joined: Mar 2005
Posts: 71
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I just read your sig, Brent
So, if you're using the MAF and bigger injectors, I can't imagine your car running properly at all with the stage 2 chips
I have a Mafterburner with these corrections as well.
Current corrections to fuel
.10v -54
.30v -54
.50v -54
.70v -25
.90v +6
1.10v +23
1.30v +27
1.50v +26
1.70v +23
1.90v +30
2.10v +30
2.30v +30
2.50v +28
2.70v +20
So, if you're using the MAF and bigger injectors, I can't imagine your car running properly at all with the stage 2 chips
I have a Mafterburner with these corrections as well.
Current corrections to fuel
.10v -54
.30v -54
.50v -54
.70v -25
.90v +6
1.10v +23
1.30v +27
1.50v +26
1.70v +23
1.90v +30
2.10v +30
2.30v +30
2.50v +28
2.70v +20
Pro
Joined: Nov 2003
Posts: 550
Likes: 10
From: Bay Area, CA
TurboTommy... what are you talking about?
"Longer stroke = SHORTER TDC dwell time (needs more advance for max power)" - Wrong.
The increased stroke and rod length of a stroker motor yields a longer piston dwell time.
http://www.fordmuscle.com/archives/2...r/index2.shtml
Becareful with timing on the 2.8 liter..
"Longer stroke = SHORTER TDC dwell time (needs more advance for max power)" - Wrong.
The increased stroke and rod length of a stroker motor yields a longer piston dwell time.
http://www.fordmuscle.com/archives/2...r/index2.shtml
Becareful with timing on the 2.8 liter..
Rennlist Member
Joined: Oct 2003
Posts: 1,589
Likes: 1
From: Ontario, Canada
sl951,
here's what I understand:
longer stroke = faster piston speeds
faster piston speeds = less time at and around TDC (or more correctly: time at smallest size of the combustion chamber) (I ignorantly don't know the correct term for this)
Fast,
it's my understanding that longer stroke needs more timing. I'm just curious why you think the Authority chips would be too aggressive?
here's what I understand:
longer stroke = faster piston speeds
faster piston speeds = less time at and around TDC (or more correctly: time at smallest size of the combustion chamber) (I ignorantly don't know the correct term for this)
Fast,
it's my understanding that longer stroke needs more timing. I'm just curious why you think the Authority chips would be too aggressive?
Pro
Joined: Nov 2003
Posts: 550
Likes: 10
From: Bay Area, CA
TurboTommy.
You're missing some things.
Longer Stroke = Faster piston speeds as it passes through the midway point (between TDC and BDC).
Think about it...... the reason for the faster piston speed is to make up for the SLOW Dwell time at TDC and BDC.
You're missing some things.
Longer Stroke = Faster piston speeds as it passes through the midway point (between TDC and BDC).
Think about it...... the reason for the faster piston speed is to make up for the SLOW Dwell time at TDC and BDC.