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Old 02-27-2012   #1
Tony Davila
 
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Exclamation Walbro 255 fuel pump?

Okay I have given up searching this forum to see if anyone has tried using the 96 7.4 Suburban Walbro fuel pump in their Z. I have to now replace my secondary and was curious if anyone has tried that pump.

Lingenfelter has a Walbro twin replacement fuel pump assembly for our cars on his website. I was contemplating using a Walbro pump on my secondaries only because I didn't want to use another Airtec if possible.

Walbro F20000169 255LPH Fuel Pump Chevrolet Suburban 1996 - 1997
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Old 02-27-2012   #2
DaveK
 
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Default Re: Walbro 255 fuel pump?

No knowledge of them myself but there was a previous post about them:

http://www.zr1.net/forum/showthread....ghlight=walbro

Maybe the posters can provide more information.

Dave
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Old 02-27-2012   #3
Tony Davila
 
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Default Re: Walbro 255 fuel pump?

Quote:
Originally Posted by DaveK View Post
No knowledge of them myself but there was a previous post about them:

http://www.zr1.net/forum/showthread....ghlight=walbro

Maybe the posters can provide more information.

Dave
Thanks..... that is what I needed to know. I did Head and Cam work on engine and now every so often it falls flat after 7k. Pump pressure was 48psi on secondary. I might just do that swap.

Tony
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Old 02-27-2012   #4
Pete
 
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Default Re: Walbro 255 fuel pump?

Quote:
Originally Posted by Tony Davila View Post
Thanks..... that is what I needed to know. I did Head and Cam work on engine and now every so often it falls flat after 7k. Pump pressure was 48psi on secondary. I might just do that swap.

Tony

Let me take a wild guess,you installed Stage I cams?

Pete
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Old 02-27-2012   #5
Tony Davila
 
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Default Re: Walbro 255 fuel pump?

Quote:
Originally Posted by Pete View Post
Let me take a wild guess,you installed Stage I cams?

Pete
You have my curiosity..... Yes I do, okay.... what is up?
I forgot to mention my wideband A/F indicates lean during that time, like it is starving for fuel.

Tony
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Old 02-27-2012   #6
Pete
 
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Default Re: Walbro 255 fuel pump?

Been saying it, i've been SCREAMING it, nobody is listening.
You can lead a horse to water you can't make him drink.

EXHAUST CAMS ARE TOO BIG

We have 3 FBI 10 second Z's big motors, they all have smaller exhaust cams then your Stage I's.

This is about as far as i will go on this matter on here as much as i wanna say more,but i will get the boot.

After you add the fuel you will be told to do a ???????? i know what it is. Can anyone else guess.
I'm here for you to guess what's coming next for your Z.

Pete

PS
Tony,i don't mean to come off strong/harsh.
I know you spend some money.
Anybody that knows me knows if you ask me a question i will give you a straight answer,as a good friend of mine (wazoo guy) told me once i'm no salesman,i love him for being straight with me and i can not argue with the truth,he's right i'm no saleman.

I don't mean to come off harsh/strong if you say the word i will delete my post just say the word.
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'91 #1635 PoloGreen 350 LT5
11.09 @ 129.27
11.04 @ 128.86
474RWHP 400RWTQ
http://www.youtube.com/watch?v=SFNFOhGGlR4
http://www.youtube.com/watch?v=ZlRIOMwaDYY
https://sites.google.com/site/peteszr1garage

Last edited by Pete; 02-28-2012 at 03:12 AM.
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Old 02-28-2012   #7
XfireZ51
 
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Default Re: Walbro 255 fuel pump?

Quote:
Originally Posted by Tony Davila View Post
You have my curiosity..... Yes I do, okay.... what is up?
I forgot to mention my wideband A/F indicates lean during that time, like it is starving for fuel.

Tony
Tony,

Does that mean your VE table is maxxed out at the top!!? Who did the tune?
Pete and I were just talking about Stage 1 cams and how really the LT-5 doesn't need more exhaust. Already pretty efficient and better breathing exhaust system makes it better. Bigger exhaust cam has too much overlap with valve closing late and taking some of the air/fuel charge out the exhaust port. FU told me once he believed the motor came "overcammed" from the factory and given the improvement we get with just porting, I agree with him. This is why I decided to onstall only a larger intake cam with my ported heads.
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Old 02-28-2012   #8
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Default Re: Walbro 255 fuel pump?

We put two Walbro's in the turbo car but I'll have to look back at the receipt to see which ones...
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Old 02-29-2012   #9
HAWAIIZR-1
 
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Default Re: Walbro 255 fuel pump?

Pete,

I'm all ears and have SGC Stage I cams too, but I don't know about any issues yet and very pleased with the way it runs. I have not flattened out at 7,200 rpms but only took it up that high once since I just broke it in and working to get pass emissions with different tune. Having said that, I'll know when I give up (fail) or pass emissions and put the headers back on with X pipe and some dynomax etc. and get it dyno tuned. I'll post the results and what issues I ran into.

I believe you if you said it about the exhaust cams as evidence by everything you have done so far and proven. Not all the tuners for the LT5 agree with each other, in fact they all seem to believe differently about certain things so understood. We all take the risks with who we believe or trusted at one time. Get me once, but you won't get me twice. Thanks for your honesty and sharing the truth.

Craig
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Old 02-29-2012   #10
Pete
 
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Default Re: Walbro 255 fuel pump?

Quote:
Originally Posted by HAWAIIZR-1 View Post
Pete,

I'm all ears and have SGC Stage I cams too, but I don't know about any issues yet and very pleased with the way it runs. I have not flattened out at 7,200 rpms but only took it up that high once since I just broke it in and working to get pass emissions with different tune. Having said that, I'll know when I give up (fail) or pass emissions and put the headers back on with X pipe and some dynomax etc. and get it dyno tuned. I'll post the results and what issues I ran into.

I believe you if you said it about the exhaust cams as evidence by everything you have done so far and proven. Not all the tuners for the LT5 agree with each other, in fact they all seem to believe differently about certain things so understood. We all take the risks with who we believe or trusted at one time. Get me once, but you won't get me twice. Thanks for your honesty and sharing the truth.

Craig
Ok,you guys asked for it LOL
I will get flack for this,oh well no guts no glory.
Let me say that any cams passed thru my hands have been checked/spec'd.

If a good tuner done some,not a whole lot just some and knows anything about performance 101 they would know that 75-80% Intake/Exhaust ratio is very good to perfect.
If they took the time and flowed LT5 heads either stock or ported they would find out I/E ratio is way above and beyond 80%.
LPE has done research on this and it shows on his LT5 cam specs he was selling.
So question is if I/E ratio is 90% do we need more exhaust especially on small cube motors.

If you guys went with Stage III intakes & Stage I exhausts with some extensive porting,i would say ok.
The issue i see with Stage I intake cams they are not much bigger if any over stock intake cams so it's like putting in big exhaust cams with stock intake cams.

The other issue is tuning it could be made to run ok but no matter what you do you'll get fumes at idle,overlap.

At this time i'm testing Stage III intake with .224 exhaust,i don't know if i went overboard with the cams for 350ci,we'll find out or will i have to go back to the smaller .236in .220ex

Need more proof i had Stage II .237 .440 cams on a 415 car made good power tuning was a mother, she ran ok but idle fumes were forget bout it.
Anyway we changed to .224 exhaust cams that was the only change we made, picked up 25-30 accross the whole RPM range tunability/driveability was way way better.
Need more proof Ted's 415 peak #'s are as good or better but look below that and forgetboutit.


Pete
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'91 #1635 PoloGreen 350 LT5
11.09 @ 129.27
11.04 @ 128.86
474RWHP 400RWTQ
http://www.youtube.com/watch?v=SFNFOhGGlR4
http://www.youtube.com/watch?v=ZlRIOMwaDYY
https://sites.google.com/site/peteszr1garage

Last edited by Pete; 02-29-2012 at 02:38 PM.
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