My PMO ITB Project

[brads911sc]

Still have alittle tuning to do at a constant 3-4k RPM's (70-90 mph highway) where I have a slight stumble.

The power curve is great and consistent from 1500-5000 rpms. I start to lose steam from 5-7k rpms. I have no complaints with WOT. For daily driving it has been good. I am still rich at cruise...

Need to do some fine tuning before I do the Dyno... or maybe not. Perhaps it would help with tuning? Just havent had much time.

Originally Posted by DW SD

Brad,
Did you ever dyno?
How did the ITBs effect area under your power curve?

Doug

[AlfonsoR]

Brad,

Very Cool and interesting project. Am I right that the PMO's have a huge performance potential? Is a monster motor (3.4 or 3.5) in your future plans?

[brads911sc]

Well my throttle bodies are 40mm, probably not big enough for a monster engine. I plan on a 3.2 SS when I start that project and Im pretty sure my 40's will work just fine for that.

I was looking to dump the CIS, get something modern and tuneable with better all around performance for the long haul that will run fine on todays and tomorrow gas. (I do use Chevron Premium).

It was a great project. Gave me exactly what I have been looking for. I have some work to do. fine tuning. Still havent installed the manual throttle (its not too cold here, not sure if Ill even do it) and accel/warm enrichments are currently turned off.

I am a constant project kind of guy... and this allows for that.
Thanks for the complements.

Brad

Originally Posted by AlfonsoR

Brad,

Very Cool and interesting project. Am I right that the PMO's have a huge performance potential? Is a monster motor (3.4 or 3.5) in your future plans?

[luvndasun]

Hi Brad - I am using the same Fuel Pressure regulator as you "Aeromotive Compact EFI Fuel Regulator 13105". On the regulator, there is what looks like a vacuum hose fitting. Does this get hooked up? Where did you run the the vacuum line to?

[kiwiokie]

Brad any update on this project? Do you have the stumble cured?

[junjun11]

Hi, since you are going to install a/c, how is the idle up going to be controlled? is it possible to use the same mechanism to control both a/c idle up and warm up?

[roland_shaak]

Originally Posted by brads911sc

Trog,

Couldnt you use the existing Air Bypass Screws on the PMO's? They are right next to the Vacuum ports. Does anything exist out there to use those ports.

Just a thought.

Brad

I had TMW's John C (owner at AEM) i flew him up in the 90's before he really hit it big with the import stuff- so the set up was
a 914 type iv at 2.6 liters pauter innards, and roller rockers with 45mm TBI's from TMW, MoTec M4, Kieth black 545 pistons in the 103 cylinders...

i had a pissy base map worked up enough to drive to to sea tac airport - i had installed a different fast reacting O2 sensor the night before. he hopped in and by the 30 miles back he darn near had it tuned perfect- using my laptop with wire dangling to the rear outside, and a fast reacting large meter in his lap- then i drove around some nice long hills for power pulls and down the same hills for lean - foot off or light on the throttle- and then some long straights then from snohomish up to skyhomish (river and mountain high altitude combination) and he nailed that baby

so cold -19 days started and ran perfect- no bypass valve, nothing matter of fact i used the ports for a LOG

an aluminum tube (thich marine grade aluminum tube closed both ends and welded i ran the vacum lines to it and the correction sifnal back to my aeromotive pressure regulator (atmoshepic correction) this was before all the tuning was done - it does two things - one it sends a "stable AVERAGED valucm signal to the ECU and to the regulator) all a/n and brake line for that mod

the tube was about 7" long and 2.5" in diameter- 4 in - two out (reg and ecu)...worked great the ECU doesn't have to successive approximate with so much swing in the vacuum signal so it is happier and a more accurate value can be derived

the injectors can be tuned to handle cold starts, in a mid cammed motor (this was a big motor - 4.125" pistons..and such with a web cam of semi aggressive profile....

once i dialed it in on the track (140 at the straight into turn one at PRI and it had more) sold the motor to a buddy to put in his ghia (he's a metal bender) and he drove it to one light and back parked it sold it to a 914 racer in San Jose

it take sa knowledgeable tuner- you can putz all you want- but after you are done it should go to a chassis dyno at a GOOD and experienced shop (look for old guys with young guys on the computer end- ya know).....

and then road tune it with an EXPERIENCED tuner...should be the same he/she will be familiar with your ride and set up

Rollo - out

PS - my RSA is using Jenevy TBI's and a MoTec m84 (may kick it up a bit not sure), areomotive regulator- custom vac log, and direct fire - getting rid of that damn dual distributor and it's belt changes..

John fell deathly ill at the sea tac terminal and was in my buddy's hospital for 2 weeks before he could fly home- pancreatic issues- no doubt from riding with me

[roland_shaak]

Originally Posted by roland_shaak

I had TMW's John C (owner at AEM) i flew him up in the 90's before he really hit it big with the import stuff- so the set up was
a 914 type iv at 2.6 liters pauter innards, and roller rockers with 45mm TBI's from TMW, MoTec M4, Kieth black 545 pistons in the 103 cylinders...

i had a pissy base map worked up enough to drive to to sea tac airport - i had installed a different fast reacting O2 sensor the night before. he hopped in and by the 30 miles back he darn near had it tuned perfect- using my laptop with wire dangling to the rear outside, and a fast reacting large meter in his lap- then i drove around some nice long hills for power pulls and down the same hills for lean - foot off or light on the throttle- and then some long straights then from snohomish up to skyhomish (river and mountain high altitude combination) and he nailed that baby

so cold -19 days started and ran perfect- no bypass valve, nothing matter of fact i used the ports for a LOG

an aluminum tube (thich marine grade aluminum tube closed both ends and welded i ran the vacum lines to it and the correction sifnal back to my aeromotive pressure regulator (atmoshepic correction) this was before all the tuning was done - it does two things - one it sends a "stable AVERAGED valucm signal to the ECU and to the regulator) all a/n and brake line for that mod

the tube was about 7" long and 2.5" in diameter- 4 in - two out (reg and ecu)...worked great the ECU doesn't have to successive approximate with so much swing in the vacuum signal so it is happier and a more accurate value can be derived

the injectors can be tuned to handle cold starts, in a mid cammed motor (this was a big motor - 4.125" pistons..and such with a web cam of semi aggressive profile....

once i dialed it in on the track (140 at the straight into turn one at PRI and it had more) sold the motor to a buddy to put in his ghia (he's a metal bender) and he drove it to one light and back parked it sold it to a 914 racer in San Jose

it take sa knowledgeable tuner- you can putz all you want- but after you are done it should go to a chassis dyno at a GOOD and experienced shop (look for old guys with young guys on the computer end- ya know).....

and then road tune it with an EXPERIENCED tuner...should be the same he/she will be familiar with your ride and set up

Rollo - out

PS - my RSA is using Jenevy TBI's and a MoTec m84 (may kick it up a bit not sure), areomotive regulator- custom vac log, and direct fire - getting rid of that damn dual distributor and it's belt changes..

John fell deathly ill at the sea tac terminal and was in my buddy's hospital for 2 weeks before he could fly home- pancreatic issues- no doubt from riding with me

here are logs to look at
Vacuum Log for 2-4-6-8 Cylinder

[brads911sc]

Sorry. I missed this.

Stumble was likely caused by a ground issue. I bumped down the voltage and it went away.

Car runs great across the powerband. I am rich in some areas, Generally 12.1-13.4 AFR's. High 13's in some areas. Just havent had the time to optimize at around 13.1. Hopefully once my summer projects are done (Im in hot humid houston), I will take it out and get some tuning done.

Originally Posted by kiwiokie

Brad any update on this project? Do you have the stumble cured?

[brads911sc]

Im in houston. I have no issues with warm up. a cold day in January here is 45 degrees for a low and 60 for a high.

But I have manual throttle from a pre-74 car that id use if needed.

I have no idle issues based on the AC.

Originally Posted by junjun11

Hi, since you are going to install a/c, how is the idle up going to be controlled? is it possible to use the same mechanism to control both a/c idle up and warm up?

[brads911sc]

Yes. It gets hooked up. I have a vacuum bar and a vacuum can (moderate sized Fuel Filter works great). I can take pics if you need it. My vacuum is steady across the entire power band.

I have my 6 ITB's plugged into the bar. The my bar plugged into a vacuum canister, then the canister plugged into a T that is connected to this port on the regulator and the ECU.

Originally Posted by luvndasun

Hi Brad - I am using the same Fuel Pressure regulator as you "Aeromotive Compact EFI Fuel Regulator 13105". On the regulator, there is what looks like a vacuum hose fitting. Does this get hooked up? Where did you run the the vacuum line to?

[GaryR]

Brad - What is the purpose of the "vacuum can" and is this what you are talking about? All of my equipment has arrived and i'm in the process of assembling/installing it. Also, where did you get the plug end for the Delco TPS that came with the kit?

[brads911sc]

Yes. That is what I used. The vacuum can stabilized and evens out the vacuum pulse / fluctuation that could impact idle with ITB's as well as a slightly more aggressive cam.

I bought all my supplies from Summit Racing. Although could get on ebay as well...

Originally Posted by GaryR

Brad - What is the purpose of the "vacuum can" and is this what you are talking about? All of my equipment has arrived and i'm in the process of assembling/installing it. Also, where did you get the plug end for the Delco TPS that came with the kit?

[Tippy]

Brad, do you run VEAnalyze Live? On easy, you can see the software circling your target AFR's until in seconds the swings get less and less and the target AFR is obtained. Pretty cool to watch.

[brads911sc]

i haven't tuned in awhile. i do have some areas that are rich. i intend to get out and tune once i am done with my summer projects... I have used it a little in the past. I didnt care for it too much in city driving tuning.

[Tippy]

Yeah, it seems to be hit or miss with me too.

[brads911sc]

I found that with frequent upshift/downshift that it took the VE values too low (not sure if that makes sense), and then I had a lean stumble in those areas on acceleration. For example, Id have a group of 6 cells where the VE was 18-20 and then 1 cell where it was a 12 or 13. It would stumble.This was very noticeable at a stop sign. when i overrode it and entered something in the 18-20 range, it did not stumble. I suppose if you scaled the table so that your low scores where in the 50's rather than teens, you could get away with it... but just preferred seat of the pants tuning knowing Id rather be rich than lean. It did however work good at highway cruise tuning at various speeds and rpms/loads because the load and rpm values were more constant.

[Tippy]

That happened to me on the latest run. Probably rerun it to get rid of it. Mine goes down to 30kPa's.

[BoxsterGT]

I know this is an old post, but how did this project turn out?

I am considering doing this myself.

Len

[dfink]

The project came out great sending you a PM