Looking great, Jack!

Gotta be a riot to drive.

Wow! Bloody hell it`s impressive! Congtrats!!!!

Awesome!!

Wow! Congratulations. What carb configuration did you end up with?

60 idle / 130 idle air correctors
f11 emulsion tube
175 main / 180 air corrector
42mm vents

Lots fuel for a 3.2

Great dyno numbers. Congrats! Did James help out with tuning as well?

Nicely balanced for the vents - more air + more fuel. Any modifications to your ignition advance curve?

Yes, 28 degrees total advance now. I put 75 more miles on this car yesterday and can’t wipe the grin off my face from 4,000-7,300 in 2nd/3rd gear. I might rear 2/3/4 sometime next year and keep my tall 5th gear. 85mph @ 3200rpm in 5th gear is really nice.

I have a dip at 4k you can see in both the torque and hp curves. The afr went rich for a split second and hits 11.8 causing the curve to dip. I would have loved to keep going and tune that out but on the last run i noticed the throttle wasn’t opening all the way so I had James really push down on the pedal and well… we bent the accelerator bell crank at the pedal assembly so we kinda ended the day there.

Up next is to fix my bent pedal bell crank, backdate my entire accelerator linkage assembly and backdate my ebrake assembly to a 74 style with the hand throttle/ebrake/2 heat levers. The CIS linkage and CIS bell crank geometry/ratio is not right for the carbs. Yes it can work, but i think there are things to do to make it better with correct pedal travel and a more linear throw. I have yet to find a perfect remedy for this on the forums so now i’m trying to take a go at it myself and see if I can get it perfect for my car. I have seen Gordo’s thread how he shortened it but I would like to experiment using all the early part numbers and see how it is. Hoping this backdate will cure that. I already shortened the linkage on pedal side of the accelerator linkage but still having issues reaching WOT. I dug through the 1971 911T parts catalog and found the rear rod (#33 below) between the coupler and bell crank is actually a different part number for the early carb 911’s thats shorter than the later CIS/Motronic rod.

All parts ordered from our host. If everything i purchased is correct, I will post a new thread with all the part numbers and instructions to help out other pelican users to properly convert a CIS/Motronic g series to carbs.

…can’t stop tinkering

http://forums.pelicanparts.com/uploa...1629313051.jpg

Biggest change you can make is to put the early bell crank (#35 in parts breakout) on the car. The angle and throw are very different compared to a CIS car. This will give you the correct angle throw to get WOT on carbs.

The throttle rod you mention is longer on the CIS car. You can shorten your existing one, cutting off the end and running a die down to repair the threads.

I’ve got full pedal travel from mine with the stock bell crank by cranking all of the pieces as tightly together as I could.

I have a full length sleeved throttle cable that I was going to use but backed out. It’s available.

I did replace the bell crank at the pedal.

You can go too far as well, make sure your pedal stops at wide open or you can cause damage to the carbs.

I spent two hours playing with the linkage and couldn’t get WOT at the pedal stop. with the linkage at the pedal tightened to the max, the coupler tightened to the max, the rod to bell crank tightened to the max, etc. I also don’t think you get the correct progressive pedal travel with the CIS bell crank. Reference attached below. Ill update this thread next week with how the new linkage is. Honestly i’m just most excited for the hand throttle to help with cold starts lol.

http://forums.pelicanparts.com/uploa...1629340586.jpg

Do you think that it is possible that the dip at 4000 rpms on your graph probably isn’t at 4000? Because you said that the rpm graph is off? I think the dip in power could be at about 2700 rpms which opens up the possibility that the dip is from the transition of the carb circuits?.

Second you mention that you aren’t getting full pedal travel, have you looked down the carbs to check that the throttles are or aren’t opening properly? I think they have to be, you got 300 HP at the wheels which is amazing, so it is unlikely that you aren’t getting full throttle.

http://forums.pelicanparts.com/porsche-911-technical-forum/948879-pmo-transition-mains.html

https://forums.pelicanparts.com/911-engine-rebuilding-forum/821976-gordos-pmo-carb-t

I believe the dip is really at around 4,400. I’m going to drive this car later this week and figure it out. It doesn’t really feel like a flat spot and I’m sure i would be fine to keep it as is and not think about it but I am really enjoying learn the process of tuning the carbs on this engine and would love to see if i could figure it out. I believe the f11 emulsion tube might need to be modified.

The throttle was opening to about 95%. There’s the tiniest amount of traveling that it’s not making. It might now be enough to actually change power but it is enough to bug me since I know it’s an issue. You see the slightest amount of movement between WOT on the pedal and then using your hand on the linkage to complete.

I'm my race prep life, engine builders have told me not to set the linkage to full wide open, but to leave them a few degrees from WOT to aid atomization of the fuel mixture. Either way, a bonified 300 wheel is kickass, man. Congrats!

Feel free to document installing the hand throttle, it's been on my list of things for my ITBs.

Linkage change is fascinating, it's one of the biggest things that bugs me about my Triumph setup. Been meaning to look into a Morse cable setup.

Interesting the dip to 11.8 caused that much of a dip in torque, it looks like 5% or more.

I'd be interested to know what the motor "liked" in terms of AFR for max power - did you play with main jets at all to check various AFR's and resulting power, or is that too time consuming to do on a dyno, with carbs?

We did play around with a few air correctors and a handful of main jets, making slow jumps up during every change. Where we ended up the engine is very happy. I believe a different e tube would bring out the rich dip.

Life picked up, i’ve been swamped. The 911 hasn’t moved out of the garage in almost a couple weeks. I’m waiting for some hand throttle parts to come in before messing with it more.

Do you have the final AFR curve?

Sick build !!