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GP2 Cam Vacuum & TBI

elysium

Senior Member
Offline
After the better part of a week battling the various and unknown demons of a rebuilt engine and a new TBI system we decided to back up and tackle one problem at a time. Despite repeated calls and a profile scan we really received little help from AFI other than "you have a vacuum leak" when we were pretty sure it wasn't the case. Unfortunately since we were installing it a newly rebuilt and unrun motor we couldn't be 100% sure since it really wouldn't run long enough to get real numbers.
In an attempt to seperate the issues we decided to go to the straight carbs and run the motor so we could evaluate it seperate from the TBI system. The car does run on the carbs although we did ID some underlyng issues. The rear carb was running very lean and we were able to get that improved but not perfect. We also found that the GP2 cam had to be set to different lash specs than stock( we didn't see that info in the materials from Goodparts that we recall)
Currently we are running the set-up on the carbs and are getting about 15-17" of vacuum at and idle of about 900 rpm with the timing set to 12 advance.If we idle it up another couple of 100 the vacuum goes to 18" steady but I don't want to battle run on if it can be avoided.
Questions:
1) Can anyone running the GP2 give me numbers for their vacuum at idle? We think this is pretty good but we don't have a comparison and aren't really sure what a stck TR6 will measure.
2) Can anyone with a GP2 or similar "mild cam" who is on TBI tell me what they are running for vacuum and advance? We are told the system should be compatible but we are pretty sure we at least need a re-programmed chip but we would like some real world numbers to know how we stand.
As always,thank you for any insights you can offer.
Elysium
Oh,BTW, we went for a few spins today AND IT WAS FREAKING AWESOME!!!!!!!
 
Stick around. I think that Bill and Tom are running with the GP-2's.
 
Tom
Thanks -I just saw it over there and followed up on 6Pack for the sake of continuity. As an aside,what scale to you train in? I saw your posts before about setting up portable layouts for away games but wasn't sure what your main activity was in.
Elysium
When I looked back in the post to check my spelling on gauge I see I mis-spelled it s-c-a-l-e
 
Elysium,
We do what is referred to "G" scale. It is a complicated size because we use common size track but run from 1:32 to 7/8's scale on it. I like narrow gage and so my models are 1:22.5 to 1:20. A way to visualize is that the box cars are about the size of a loaf of bread.
I build many of my models and do the lettering and art work on them.
My favorite train is a mining train I built. Shirley and I donate a lot of time to charity for different organizations as well as running at nursing homes, schools, and hospitals.
Our most popular train with the public is our 100 foot long circus train. Because of the length we do not often have room to run it. It is one of the most photographed model trains in the country and has been in several magazines and on TV many times.
Here are a few of the wagons and cars I built for the circus train.
https://www.britishcarforum.com/bcforum/ubbthreads.php/topics/488072/State_Fair_Exhibit#Post488072
 
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