Really admire your tenacity and ability to figure out the nuances of these old carbs. When they’re dialed in, it’s such a sweet sound, but it’s not easy. Hope to see you and your 911 at some of the local PCA events someday. 👍🏼👏🏼👏🏼👏🏼👏🏼👏🏼
Good to see you making progress. I've been particularly interested in this project as I just had a 2.7 build with Clewett throttle bodies and Haltech electronic fuel injection and ignition in my 1972 911 finish this last July. Just a heads up, you're going to need a lot of dyno time to get it running right. So far I've been mostly pleased with the result. The car starts and idles great no matter what temperature the engine is and the throttle response and acceleration is crazy! We initially ran into some of the same problems you are having adjusting the TB's additionally, we had to go to an older analog TPS as the digital TPS we got from Haltech was too jumpy to tune accurately. Seemed as though some electrical noise in the system couldn't be isolated, however, the analog TPS fixed that issue. I've driven the car nearly 2000 miles from July to the first week in November (winter here now) one of the issues I'm still not completely happy with is I'm still getting a backfire above 2500 rpm when letting off of the throttle and coming back in as in normal driving. If you let off the throttle completely and let the rpm drop below the 2500 level before tipping the throttle back there's no back fire, also if you can very lightly and slowly tip the throttle in you can get by with no backfire but it takes a smooth road and a bit of concentration. I think it all comes down to getting finer range control on the TB's when they first open at higher RPM. Air control with these set ups is crucial. While I realize a lot of guys pay for the backfiring I'd love to find a way to get around that. I'll be interested in what you discover as you finish with your build. Take care.
Thank you and great to hear about your experiences too. You are right, I still have a long road ahead, but hope to conquer this eventually. Good info about the TPS. My software allows for some digital filtering which seems to help noisy inputs. I have no idea yet how to prevent backfires but will cross that bridge eventually. Is it an exhaust or intake backfire?
@@GarageTimeAutoResto Exhaust - we are still working on it. The car is put away due to weather here but will follow up late Feb or March when we start to tackle it again
I have a 3.2 with haltech, no ITBs though. I'm having some weird issues that seem like something with the TPS too. Which TPS did you end up going with to solve that? I was seeing a lot of noise in the throttle position derivative channel in the logs. Upping the TPS derivative rate percentage cut all that out, so I'm assuming it's a bad TPS. I haven't had a chance to swap it out to a new one yet to make sure.
Wow 😮it sounds really good even jyst at idle . Good for you Tom figureing out all the necessary engineering fir your ITB ‘s When you figure out all the “gremlins “ it is so much more rewarding. 😊
Wow, so the PMOs are gone! I'm happy you got a good solution now even if it was costly. I spent a lot of time on cold starts too - these cars need a good amount of extra fuel and air when completely cold. My MicroSquirted 3.0 (SC Euro) motor with 993 plastic intake likes to idle quite high initially (~1400rpm) before I bring down slowly to a stock idle (~900rpm.) As they say, give the motor what it wants...
Yes a new era😀. You are right about lots of fuel at startup. The frustrating thing is my wideband o2 sensors don't come online until it's too late to read. I bet there's is a way to start them up early before cranking.
I can’t believe it. I hadn’t thought about you in months until yesterday and here you are today. Out has happened to me several times. Can the internet read our minds?
Simplicity is not associated with ITBs. I am amazed that in 2024 there is not a bolt-on kit that works well out of the box considering the excessive cost involved. Thanks for bringing us along on Macs air/fuel journey.
For sure, it's a journey. To be fair Kinsler does sell a nice package, but still requires tons of wiring and tuning. The tough thing is every engine is different. I would be surprised if an out of the box solution would work?
Great update. interesting, my V12 has a central pivot with a linkage to each bank. I'll have to check to see the shape and how it handles tip in. It has a wire cable run to the throttle pedal. No drive by wire. Do you plan on taking it to a rolling road?
Without knowing the cable you're going to use, I would be concerned with the cable stretching between the banks over time. I've enjoyed your clips very much!
What motor is this on? 3.0 or 3.2? I just got a set of PMO ITBS 50mm for my 3.2 and will do a cam and now I'm a bit worried haha. How is it that others have been able to setup their idle fine with this same setup?
3.2L, my guess the cam profile makes a big difference. Every engine behaves different. You can reach out to me directly if you want to discuss. Why did you choose 50mm?
Have you pinpointed the most difficult part of efi? Is there a certain thing that is difficult? I’m planning to build a 3.2 carrera and obviously going to efi, but I’m also a computer nerd so I was hoping this would be the easy part for me
@tylerwelker Are you keeping the stock Motronic ECU or going standalone? EFI is hard because the tuner has to anticipate what the engine needs. It's like tuning carbs, but instead of replacing parts you tweak parameters in software instead. Lots of tuning and engine theory experience is needed.
Thanks for all your support and patience. 😊 Cold start at the end of this video has already been resolved. Starting to get the hang of this!
Thank you Tom...been waiting for your update...love your videos! Pius
Really admire your tenacity and ability to figure out the nuances of these old carbs. When they’re dialed in, it’s such a sweet sound, but it’s not easy. Hope to see you and your 911 at some of the local PCA events someday. 👍🏼👏🏼👏🏼👏🏼👏🏼👏🏼
Thank you. I I look forward to making loud noises soon. Are you in SoCal?
It warms my heart to see this EFI ITB project alive again. Great job Tom!
Thank you Patrick! Can't wait to hear yours running soon too .
Thanks for the update and really glad to see Mac back in the garage and making progress.
I'm relieved to overcome another big obstacle
Good to see you making progress. I've been particularly interested in this project as I just had a 2.7 build with Clewett throttle bodies and Haltech electronic fuel injection and ignition in my 1972 911 finish this last July. Just a heads up, you're going to need a lot of dyno time to get it running right. So far I've been mostly pleased with the result. The car starts and idles great no matter what temperature the engine is and the throttle response and acceleration is crazy! We initially ran into some of the same problems you are having adjusting the TB's additionally, we had to go to an older analog TPS as the digital TPS we got from Haltech was too jumpy to tune accurately. Seemed as though some electrical noise in the system couldn't be isolated, however, the analog TPS fixed that issue. I've driven the car nearly 2000 miles from July to the first week in November (winter here now) one of the issues I'm still not completely happy with is I'm still getting a backfire above 2500 rpm when letting off of the throttle and coming back in as in normal driving. If you let off the throttle completely and let the rpm drop below the 2500 level before tipping the throttle back there's no back fire, also if you can very lightly and slowly tip the throttle in you can get by with no backfire but it takes a smooth road and a bit of concentration. I think it all comes down to getting finer range control on the TB's when they first open at higher RPM. Air control with these set ups is crucial. While I realize a lot of guys pay for the backfiring I'd love to find a way to get around that. I'll be interested in what you discover as you finish with your build. Take care.
Thank you and great to hear about your experiences too. You are right, I still have a long road ahead, but hope to conquer this eventually.
Good info about the TPS. My software allows for some digital filtering which seems to help noisy inputs.
I have no idea yet how to prevent backfires but will cross that bridge eventually.
Is it an exhaust or intake backfire?
@@GarageTimeAutoResto Exhaust - we are still working on it. The car is put away due to weather here but will follow up late Feb or March when we start to tackle it again
Best of luck, my shot in the dark is decel fuel cut parameters
@@GarageTimeAutoResto I agree!
I have a 3.2 with haltech, no ITBs though. I'm having some weird issues that seem like something with the TPS too. Which TPS did you end up going with to solve that? I was seeing a lot of noise in the throttle position derivative channel in the logs. Upping the TPS derivative rate percentage cut all that out, so I'm assuming it's a bad TPS. I haven't had a chance to swap it out to a new one yet to make sure.
Wow 😮it sounds really good even jyst at idle . Good for you Tom figureing out all the necessary engineering fir your ITB ‘s
When you figure out all the “gremlins “ it is so much more rewarding. 😊
Thanks! I'm going to get the most out of this engine. It should be fun to drive
Well done sir!
Super glad Mac is back
Wow, so the PMOs are gone! I'm happy you got a good solution now even if it was costly. I spent a lot of time on cold starts too - these cars need a good amount of extra fuel and air when completely cold. My MicroSquirted 3.0 (SC Euro) motor with 993 plastic intake likes to idle quite high initially (~1400rpm) before I bring down slowly to a stock idle (~900rpm.) As they say, give the motor what it wants...
Yes a new era😀. You are right about lots of fuel at startup. The frustrating thing is my wideband o2 sensors don't come online until it's too late to read. I bet there's is a way to start them up early before cranking.
I can’t believe it. I hadn’t thought about you in months until yesterday and here you are today. Out has happened to me several times. Can the internet read our minds?
Strange. I've been wanting to make this video for months, so we must be synched.
Good to see it come back, just be glad it not the MFI, you could still be chasing it. It’s now a “Sport Purpose Wagon”
You are ready for RGruppe
MFI seems really difficult. Plastic stacks with ball cup linkages everywhere, yikes.
So excited about this car! Top notch!
Thank you so much for sharing when things do not go perfect, I think you just saved me a huge amount of hassle. Keep up the good work!
Your welcome, it happens to all of us.
G'day,
Thanks for the update.
✌️ Peace from Melbourne Australia
Is there anything more complicated than ITB’s ? Congratulations on the hard fought success so far. Don’t loose faith, you’ll get there.
Yes, I will get there no doubt. So many cars with ITBs are for sale. I refuse to be that guy, ha ha.
I think six webers would be worse. LoL.
Simplicity is not associated with ITBs. I am amazed that in 2024 there is not a bolt-on kit that works well out of the box considering the excessive cost involved. Thanks for bringing us along on Macs air/fuel journey.
For sure, it's a journey. To be fair Kinsler does sell a nice package, but still requires tons of wiring and tuning. The tough thing is every engine is different. I would be surprised if an out of the box solution would work?
Great update. interesting, my V12 has a central pivot with a linkage to each bank. I'll have to check to see the shape and how it handles tip in. It has a wire cable run to the throttle pedal. No drive by wire. Do you plan on taking it to a rolling road?
Drive by cable,ha ha. Please share a pic of the v12 setup on Monday if you can make it.
The old 944 had a "nautilus" style throttle pulley
Yes, like that.
Without knowing the cable you're going to use, I would be concerned with the cable stretching between the banks over time. I've enjoyed your clips very much!
Stay tuned, the cable goes down to the transmission.
The links to each bank will be solid pushrods.
Sorry about the confusion.
What motor is this on? 3.0 or 3.2?
I just got a set of PMO ITBS 50mm for my 3.2 and will do a cam and now I'm a bit worried haha. How is it that others have been able to setup their idle fine with this same setup?
3.2L, my guess the cam profile makes a big difference. Every engine behaves different. You can reach out to me directly if you want to discuss. Why did you choose 50mm?
@@GarageTimeAutoResto I'd love to give you a shout - whats the best way to get in touch?
@quintencurtis7667 You can email me at tperazzo@gmail.com
Have you pinpointed the most difficult part of efi? Is there a certain thing that is difficult? I’m planning to build a 3.2 carrera and obviously going to efi, but I’m also a computer nerd so I was hoping this would be the easy part for me
@tylerwelker Are you keeping the stock Motronic ECU or going standalone?
EFI is hard because the tuner has to anticipate what the engine needs. It's like tuning carbs, but instead of replacing parts you tweak parameters in software instead. Lots of tuning and engine theory experience is needed.