Issues With Performance Engine in Autotrans FI Bus

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Amskeptic
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Re: Issues With Performance Engine in Autotrans FI Bus

Post by Amskeptic » Tue Mar 25, 2014 11:00 am

Boxcar wrote:Thanks Colin,
a Bentley,yes have that.
I will look but thank you for adding some insights to the autotrans pressure checks.

vacuum at idle was around 10# when I last checked in the fall(low yes). As I added aux air regulator it was less,but idle went up so around 10# still@ 1025/1050rpm.
Fuel pressure regulator was "disgruntled" issuing out of spec. fuel pressure, but proper according to present low manifold vacuum.
Pressure check of trans should be interesting though. I considered it before,but look forward to dialing it in to best advantage.
Seeing as you need a 13-15 in vacuum, how do you plan to proceed? Any conversation with the engine builder / 9550 cam recommender?

I know that I have annoyed some people right here on the forum for "pissing on their performance parade" when all I really wanted was for them to be happy.
Colin :-({|=
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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Bleyseng
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Re: Issues With Performance Engine in Autotrans FI Bus

Post by Bleyseng » Tue Mar 25, 2014 1:21 pm

Ah, but the 9550 cam is for a manual 4 speed bus engine as the lower than stock idle vacuum is a known feature of the cam. It's based on the Web73 cam which is in fact based on the early 411 dual carb cam profile. When VW went with Djet FI they switched to a cam with a 15" of idle vacuum for the Djet to work. This carried over to the Ljet cams too and is why when a old engine loses compression below 90 psi, they don't run so well. For a manual transmission car, low idle vacuum causes the crappy cold start syndrom but once it warms up a bit they run great. The 411's did in fact come with auto transmission but I recall they came with FI. This early carbed 411 was in Europe so it was a 4 speed car.
For a auto bus, I would install the Web142 cam which is the 914 2.0L cam and has lots of idle vacuum (15"). Mixing and matching cams doesn't always work so good homework is needed before building a engine.
Geoff
77 Sage Green Westy- CS 2.0L-160,000 miles
70 Ghia vert, black, stock 1600SP,- 139,000 miles,
76 914 2.1L-Nepal Orange- 160,000+ miles
http://bleysengaway.blogspot.com/

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Amskeptic
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Re: Issues With Performance Engine in Autotrans FI Bus

Post by Amskeptic » Tue Mar 25, 2014 2:58 pm

Bleyseng wrote:Ah, but the 9550 cam is for a manual 4 speed
Do the cam builders/purveyors point out these vacuum issues or specify recommended applications for their cams, Bleyseng?
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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Bleyseng
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Re: Issues With Performance Engine in Autotrans FI Bus

Post by Bleyseng » Tue Mar 25, 2014 4:33 pm

Raby did as you had to go thru the "Cam Doctor" process.
I am not sure what all Webcam says to you but they do have people to talk to that recommend what cam to use if you call them. All this is moot if you just do a online order. If you do that, then lots of homework reading all the info out there is required before clicking " order this".
Geoff
77 Sage Green Westy- CS 2.0L-160,000 miles
70 Ghia vert, black, stock 1600SP,- 139,000 miles,
76 914 2.1L-Nepal Orange- 160,000+ miles
http://bleysengaway.blogspot.com/

Boxcar
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Re: Issues With Performance Engine in Autotrans FI Bus

Post by Boxcar » Tue Mar 25, 2014 7:39 pm

Thanks for the help.

I will live with these low vacuum numbers, and learn,and work things as best as I can.

This engine combo has 10K miles on it now,and overall I am happy.I picked the parts, built,and somehow short circuited the vendor's questions pertainent to this auto trans app. (bought the 9550 cam/lifters used)That IT Took three stages of engine/trans drops,and interim cheap head use,auto trans repair/ rebuild exhaust backdate,sold my 914 to fund the heads,all good stuff to get this far, is due my sticking to the project. My not unlimited funds and partially informed purchasing have to be chalked up to experience.
I purposly built with 8.6:1 CR. Still gathering some experience on THAT.

So,Piss on! Colin.You bringup solid,insightful points, already have supplied solid advice, which other web places obfuscated, and vendors missed.Thanks to YOU and your IAC place in the web!
I only found it since I upgraded my phone,websurfed more easily in jan/14. Yes smartphone only.Had I been able to find IAC as easily as I do now,when I was scrimping,living in my shop to afford heat to envelop a shop @70° in which to engine build through winter,I would have made a better informed decision.
The 9550 cam came from a high altitude arizona T4 store customer who could not run it due to descending altitude increasing his dynamic CR. Cam and lifters,just broken in, 40$IIRC. He switched cams, and CR too.

He DID however split the cases and Do The Right Thing.( Desertbusman 72?) His downsides were much more dire however.
If mine are to cope with a chronic condition I will. Looking into how my trans pressures are affected, and working on FI pressure regulator/mixture adjustment, then ignition refinements are my path for 2014.

Right now the Westy's plugs look ok. mileage is good.power is as I have never enjoyed in this Breadloaf rescue.Starts great.Idles well.
Now exploring trans pressures & 3>2 downshift @40 that feels abusive and thats where I will work.
Am I going to split the cases? Not for the cam at this time. If there is a better cam for automatic?I am all ears.Thanks Bleyseng and Colin. Learning is something I still can do! :-)
1975 003 Auto Westy L90D

repair!!!!aug2015
Jan/16 Bumped mixture a few notches richer. finally developing HP.


1.8L/LJet/Pertron DVDA+PertronixCompufire 42/36Ham Heads/AA 93mm pistons/barrels.Porsc.Swiv.Adjusters/CromoSteel pushrds/ Web 9550Cam/55cc chmbr.,035 squish,8.6:1CR/German Supply VWCanadaReman Rods/Schadek 26mmPump/vdo dualOP8/10#low sender/Quart Deep Sump
Backdate Htr bxs,reflanged 914 4into1. Two and three eighths inch collector,magniflow*muffler

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Amskeptic
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Re: Issues With Performance Engine in Autotrans FI Bus

Post by Amskeptic » Wed Mar 26, 2014 7:33 am

Boxcar wrote:Thanks for the help.
I will live with these low vacuum numbers and work things as best as I can.
This includes:
A) increasing the cross sectional area of your plenum-to-vacuum hose-to-modulator.
B) slipping in a little additional timing at idle if your vacuum gauge says to.
C) optimizing the health of the transmission with clean fluid at the correct level
D) executing a driving technique that reduces shock
E) reducing your idle speed if you can (again looking at the vacuum gauge) to reduce engagement shock
F) make sure your CVs are secure and well lubricated

We'll have a chat at your next engine overhaul . . .
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

Boxcar
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Re: Issues With Performance Engine in Autotrans FI Bus

Post by Boxcar » Wed Mar 26, 2014 12:33 pm

A. thru F. are all good stuff.

The interplay of B. and E., yes I will.

C.D.F. have been daily orders as this Bus's driver.

Once I replumb A. and observe change,perhaps I will do the same for the FI pressure regulator also.


thanks for the !thought! on( A.) though. I was pondering this when I straightened out the hoses for the DVDA distributor.

more later, I am sure.



Next overhaul I will certainly be in IAC contact over and out.
1975 003 Auto Westy L90D

repair!!!!aug2015
Jan/16 Bumped mixture a few notches richer. finally developing HP.


1.8L/LJet/Pertron DVDA+PertronixCompufire 42/36Ham Heads/AA 93mm pistons/barrels.Porsc.Swiv.Adjusters/CromoSteel pushrds/ Web 9550Cam/55cc chmbr.,035 squish,8.6:1CR/German Supply VWCanadaReman Rods/Schadek 26mmPump/vdo dualOP8/10#low sender/Quart Deep Sump
Backdate Htr bxs,reflanged 914 4into1. Two and three eighths inch collector,magniflow*muffler

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