TPI Articlke; ALL TPI answers; in my opinion...
#1
TPI Articlke; ALL TPI answers; in my opinion...
THis is good stuff - found it in a vette magazine in '01.
Note the reference to intake flow being based on the LB9 305 TPI intake flow. The author knows his stuff (never mind my highlights - I DON'T make any claim to know his stuff).
Print it out, and put it in the 'Library', where the seat has a BIG hole in the middle.
Some parts you might not understand. Re-read over and over, and it will all come to you - guaranteed.
Note the reference to intake flow being based on the LB9 305 TPI intake flow. The author knows his stuff (never mind my highlights - I DON'T make any claim to know his stuff).
Print it out, and put it in the 'Library', where the seat has a BIG hole in the middle.
Some parts you might not understand. Re-read over and over, and it will all come to you - guaranteed.
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#9
Re: TPI Articlke; ALL TPI answers; in my opinion...
Then get him to post here that he's wrong.
ed,:
Here's his web page:
http://www.raytbohacz.com/
Most links on his page defer to HEMMING'S web servers.
Looks like Hemmings stands behind him. But Hemming's doesn't know cars either ... do they?
#10
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Car: 82 Z28
Engine: 383 SP EFI/ 4150 TB
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Axle/Gears: QP 9" 3.73
Re: TPI Articlke; ALL TPI answers; in my opinion...
You are the one presenting it to this forum as the holy grail of TPI info and taking as gospel a 3rd parties information which is erroneous and misleading.
People who own a TPI /TBI engine ( do you ?) know better .
In this case ,all it is doing is perpetuating a long held myth held by newbies and the ignorant that the OP switch will save their engine.
PS.
Loving the "us" from the man who has been here a week
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Car: 82 Z28
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Re: TPI Articlke; ALL TPI answers; in my opinion...
The myth I was talking about
Think again
the ECM runs the pump relay .KO and anytime the ECM is receiving a ref signal from the dist to indicate engine is turning over.
OP switch closes @ 4 psi to run the pump direct from the battery.
If you can read a circuit diagram you will see each is mutually exclusive.if the OP drops and the OP switch opens the pump will still receive power
from the relay.
(The OP switch is in place as a backup ,so that if you loose the pump relay you can still start the engine (albeit with extended cranking )
with the pump powered from the OP switch)
3rd Gen wiring.
Easier to read Vette pump diagram
Think again
the ECM runs the pump relay .KO and anytime the ECM is receiving a ref signal from the dist to indicate engine is turning over.
OP switch closes @ 4 psi to run the pump direct from the battery.
If you can read a circuit diagram you will see each is mutually exclusive.if the OP drops and the OP switch opens the pump will still receive power
from the relay.
(The OP switch is in place as a backup ,so that if you loose the pump relay you can still start the engine (albeit with extended cranking )
with the pump powered from the OP switch)
3rd Gen wiring.
Easier to read Vette pump diagram
#15
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Car: 82 Z28
Engine: 383 SP EFI/ 4150 TB
Transmission: T400
Axle/Gears: QP 9" 3.73
Re: TPI Articlke; ALL TPI answers; in my opinion...
FWIW.
There are a multitude of ancient tech articles from the same time frame as this one where a established tech writer has made fundamental errors
when transitioning from their carb experience to EFI.
In this case the only experience the writer probably had with a oil pressure operated fuel pump switch would have been as a safety cutout on a carb car.
Just a shame the OP choose to highlight that comment so it sticks out like a proverbial
There are a multitude of ancient tech articles from the same time frame as this one where a established tech writer has made fundamental errors
when transitioning from their carb experience to EFI.
In this case the only experience the writer probably had with a oil pressure operated fuel pump switch would have been as a safety cutout on a carb car.
Just a shame the OP choose to highlight that comment so it sticks out like a proverbial
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Car: 1989 Camaro RS
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Transmission: t-56
Re: TPI Articlke; ALL TPI answers; in my opinion...
the interesting part is how similar the TPI model is to the newer LS1 computers. and.. for that matter.. how similar the TPI way of doing things is to the LS1 generation. all the LSx did was take both the MAP and MAF models above and turned them into a hybrid and nicely redundant system.
Model a buddy figured out:
CAM1 (Cylinder Airmass Model)= 20*(A*MAFhz^3+B*MAFhz^2+C*MAFhz+D)/(CYL*RPM)
CAM2= IPW*IFR*AFRwb
CAM3= GMVE*MAP/TEMP (GMVE is just a GM term for a general physics term.. ill find it later)
GMVE= CYLVOL*VE/R
TEMP= IAT+(ECT-IAT)*BIAS
seems like in the early EFI days, gm used CAM2 and 3 or CAM1 and 2 depending on the year/model then later went to the 3 airmass model. neat.
Model a buddy figured out:
CAM1 (Cylinder Airmass Model)= 20*(A*MAFhz^3+B*MAFhz^2+C*MAFhz+D)/(CYL*RPM)
CAM2= IPW*IFR*AFRwb
CAM3= GMVE*MAP/TEMP (GMVE is just a GM term for a general physics term.. ill find it later)
GMVE= CYLVOL*VE/R
TEMP= IAT+(ECT-IAT)*BIAS
seems like in the early EFI days, gm used CAM2 and 3 or CAM1 and 2 depending on the year/model then later went to the 3 airmass model. neat.
#17
Re: TPI Articlke; ALL TPI answers; in my opinion...
Don't need to .
You are the one presenting it to this forum as the holy grail of TPI info and taking as gospel a 3rd parties information which is erroneous and misleading.
People who own a TPI /TBI engine ( do you ?) know better .
In this case ,all it is doing is perpetuating a long held myth held by newbies and the ignorant that the OP switch will save their engine.
You are the one presenting it to this forum as the holy grail of TPI info and taking as gospel a 3rd parties information which is erroneous and misleading.
People who own a TPI /TBI engine ( do you ?) know better .
In this case ,all it is doing is perpetuating a long held myth held by newbies and the ignorant that the OP switch will save their engine.
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Car: 1983 G20 Chevy
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Re: TPI Articlke; ALL TPI answers; in my opinion...
I also see many glaring errors. Such as stock fuel pressure often varied widely. The stock 350 injectors were 22 lb/hr, not 24. Along with numerous other errors along the way. I also love how they claim a stock 305 does not respond to a runner upgrade, they most certainly DO.
#19
Re: TPI Articlke; ALL TPI answers; in my opinion...
I also see many glaring errors. Such as stock fuel pressure often varied widely. The stock 350 injectors were 22 lb/hr, not 24. Along with numerous other errors along the way. I also love how they claim a stock 305 does not respond to a runner upgrade, they most certainly DO.
You're doing the same thing VetteOz did - making vague accusations of many glaring errors but only mentioning a couple of not so glaring errors. I know the stock 350 injectors were 22lb /hour but I'm pretty skeptical that fuel pressure "often varied widely". Instead of making blanket unsupported assertions, how about mentioning only specific examples so readers like me know what to (perhaps) believe?
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