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L18 8.1L swap resource thread

Lets talk this P59 ecm for a moment, if I understand correctly its "the" ecm for for any of the new LS engines correct? So I dhould be able to get a good used core from any LS engine and reprogram it with my specs , it doesnt nee to be for a 8.1?
 
I believe the early LS swappers prefer the P59 but not sure as I don’t follow Gen III’s much. Your other questions would be good to ask a tuner that does that type of stuff. I can tell you this much, Howell programmed both of my ECM’s with an early 5.3L Vin for the sake of having the mechanical throttle bin files then they dumped 8.1L spark and fuel maps over that.

Took the ole girl to the exhaust shop this afternoon. I’m getting concerned this cam maybe too big. The lope is nice but I wasn’t hoping for this much lope. We’ll see once it gets quieted down and back home.
Loading her on the trailer. 8.1L Silvy pulling 8.1L Suburban
 
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Awesome , your filling in the holes to thr info I have been finding
 
It’s back from the exhaust shop. Sounds good, does have noticeable cam lope….perhaps more than I wished for but still sounds pretty cool. Also has a noticeable idle surge from the tune not matching the cam. You can tell a true cam lope from a tuning problem surge easily. Now that I can hear myself think with the exhaust fixed, the issues list is growing by the minute. Lots of issues to iron out but the hilarious thing is I don’t have a single code. The biggest issue that is screwing me up is the fact I have been waiting on a 4 core radiator since Valentine’s Day. Two have shown up shipped by two different shippers (FedEx first and UPS second) but both were beat beyond use when they arrived and the next one is being drop shipped directly from the supplier in Canada (Spectra) so who knows how friggen long that will take, eh. Right now it won’t run but 10 minutes or so before it gets hotter than hell so that makes it difficult to work on other things. Also have a rear main seal pump oil like the BP Deep Water Horizon, which really pisses me off as the trans is going to have to come out now. I’ll update the Polar Bear thread this weekend as I get time. Anybody know of a good tuner that can do a decent tune without having the luxury of doing a live tune? I’m not sure if my TunerPro crap will datalog OBDII as I haven’t tried before. I have a call into Troy at Howell but he is off until Monday
 
Ah, HA!! I just found something that is the cause of the idle surge. The ECM is not seeing the TPS signal. That is why it idles fine until I crack the throttle then it relaxes to and up and down surge. It finally logged two TPS codes after several key cycles. I may not have as big as tuning problem as I thought. That gives me a project to chase tomorrow. Moving this discussion to the PB thread.
 
http://www.dartheads.com/products/i...ig-block-chevy-8-1-liter-intake-manifold.html

When I picked up my engine the other night my buddy also gave me this intake . He needed hood clearnce for his project and hisnplan was to use this intake and a aftermarket 4bbl throttle body.

After some re reading and some research it sounds like its doable for less money then the raylar mods to the stock intake .

The problem is the mass air flow meter , can this be tuned out or located in a 14"'aircleaner base somehow? Or would I need a carb hat and piping similar to your setup ?
 
Put a 90 degree elbow on it with a big round throttle body like drag racers do when they run sfi and a 4bbl type intake.
 
yellowK20 said:
http://www.dartheads.com/products/i...ig-block-chevy-8-1-liter-intake-manifold.html

When I picked up my engine the other night my buddy also gave me this intake . He needed hood clearnce for his project and hisnplan was to use this intake and a aftermarket 4bbl throttle body.

After some re reading and some research it sounds like its doable for less money then the raylar mods to the stock intake .

The problem is the mass air flow meter , can this be tuned out or located in a 14"'aircleaner base somehow? Or would I need a carb hat and piping similar to your setup ?
Click to expand...

Why would you want to run that DART intake? I could see using that if you plan on running a carb and distributor in some old muscle car but for port injection the stock intake is the best thing you could ask for. I supposed you could drop some aftermarket TBI unit on it like FAST efi or something but not sure you would be any further a head.
 
Larry said:
Why would you want to run that DART intake? I could see using that if you plan on running a carb and distributor in some old muscle car but for port injection the stock intake is the best thing you could ask for. I supposed you could drop some aftermarket TBI unit on it like FAST efi or something but not sure you would be any further a head.
Click to expand...


Because it flows better then a raylar modifed stock intake , it has fuel injector bosses machined in so the stock fuel rails and injectors will work. yes I could do a 90 degree elbow and a L29 throttle body . But I could also use this
http://www.efisupply.com/images/dfi/dfi4bbl.pdf it uses a GM TPS and IAC .

Overall it just give me more power and easier packaging but still allows the use of the stock ecm and it was free , so I dont have to use it but I cant see a reason not too.
 
yellowK20 said:
Because it flows better then a raylar modifed stock intake , it has fuel injector bosses machined in so the stock fuel rails and injectors will work. yes I could do a 90 degree elbow and a L29 throttle body . But I could also use this
http://www.efisupply.com/images/dfi/dfi4bbl.pdf it uses a GM TPS and IAC .

Overall it just give me more power and easier packaging but still allows the use of the stock ecm and it was free , so I dont have to use it but I cant see a reason not too.
Click to expand...


Okay, if you want to go that route. Not only sounds expensive, but sounds like a tuning nightmare. I’m having a tuning nightmare of my own with just a little cam. That sounds like a really big tuning nightmare. Hope you have better tuners up there than we have down here.

Check out the “8.1L Info Swap Classifieds” group on Facebook. Lots of guys doing oddball things there that might be up your alley.
 
Larry said:
Okay, if you want to go that route. Not only sounds expensive, but sounds like a tuning nightmare. I’m having a tuning nightmare of my own with just a little cam. That sounds like a really big tuning nightmare. Hope you have better tuners up there than we have down here.

Check out the “8.1L Info Swap Classifieds” group on Facebook. Lots of guys doing oddball things there that might be up your alley.
Click to expand...



price wise it will be around 1000.00 cheaper then what I was gonna do . Especially when you consider shipping .


tuning, that has me a little concerned . As far as Ive found no one has tried this combo yet . But on paper there is no reason it shouldn't work ..... I will check that page out when I get a chance .


As for the MAF sensor, can it be tuned out??
 
yellowK20 said:
price wise it will be around 1000.00 cheaper then what I was gonna do . Especially when you consider shipping .


tuning, that has me a little concerned . As far as Ive found no one has tried this combo yet . But on paper there is no reason it shouldn't work ..... I will check that page out when I get a chance .


As for the MAF sensor, can it be tuned out??
Click to expand...


:haha: Tuning out a MAF = speed density fuel calculations = :poo:

Think of TBI. TBI is speed density fuel calculations and is a bigger nightmare to tune once it has been fondled with.
 
Tune out the mass air flow sensor? Kind of defeats the whole purpose of having computer controlled fuel injection. MAF is the best tech we have to meter air I to the engine. Without that you can't inject the precisely correct amount of fuel.
 
Diesel guy , I was just wondering makes it easier since Incould run a 14" round aircleaner and not have to deal with all the ugly piping and elbows
 
My friends did an 8.1L swap to his 72' K20 with 4l80e and np241 case recently.

Things they used
- Denali radiator
- Stock Intake
- 8.1 with comp cam
- Blackbear tune (they are datalogging it right now, to send in)
- Used stock motormounts that were in the k20
- Suburban fuel tank with in tank pump
- Lokar shifter


Overall this thing is a monster, if the truck could handle going over 105mph safely it would do it with ease. It's on 35's and 4.10's gears but this thing has some diesel torque. Can't wait till they program the stupid torque management out of the motor. After riding in this I think that i'm gonna do a 8.1 swap myself in the K5.
 
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