305 to 350 swap ecm/prom question
11-27-2009, 05:24 PM
#1
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Car: 1998 grand cherokee, 1988 iroc z
Engine: 350 tpi
Transmission: 700r4
Axle/Gears: ???
305 to 350 swap ecm/prom question
I got an 85 z28 tpi. it has the 305 in it now. i want to stay with the tpi on the 350.
I know I need to get a 350 prom for the 85 ecm.I know the only '85 350 prom is from a vette.
if I put my current tpi on this 350 it should just bolt on? the block is from 1989 and it came out of a truck.
if i get a ecm with a 350 prom from a different year that uses maf will my current 85 wire harness work with the ecm/prom or do i need to have the same year harness, ecm, and prom.
I know I need to get a 350 prom for the 85 ecm.I know the only '85 350 prom is from a vette.
if I put my current tpi on this 350 it should just bolt on? the block is from 1989 and it came out of a truck.
if i get a ecm with a 350 prom from a different year that uses maf will my current 85 wire harness work with the ecm/prom or do i need to have the same year harness, ecm, and prom.
11-27-2009, 06:01 PM
#2
Re: 305 to 350 swap ecm/prom question
you got a unique setup on your hands. Let me tell you what I did with my 86 IROC. The ECM is an original that supported the 305. Before my engine threw a rod, I switched the 305 prom with a 87 350 PROM that had a HyperTech chip. I experimented with the 86 and 87 PROMs, ECM's and vice versa. Given that my IROC had a 350 instead of a 305, there was no difference that I noticed when I switched out everything. Here is a link that you can use to verify the engine block casting number.
http://www.chevy-camaro.com/chevy-ca...es.asp?group=6
http://www.chevy-camaro.com/chevy-ca...es.asp?group=6
11-27-2009, 06:01 PM
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Car: 1987 camaro iroc
Engine: 350
Transmission: 5 speed borg warner
Axle/Gears: 3.45
Re: 305 to 350 swap ecm/prom question
Here is all the info you need.Troc
305 TPI to 350 TPI Conversion
If you are looking to convert your car from a 305 TPI to a 350 TPI setup, then you should find the information below rather useful. These are all the needed changes to do the conversion.
First of all, the TPI intakes (manifold, plenum, fuel rails, throttle body, runners) were exactly the same between 305 and 350 engines of the same year. There were no differences in these parts whatsoever between one engine size and the other during any year (there were however differences between the intake manifold and fuel rails between the Camaros and Corvettes). For example, a 1987 intake was the same for both a 305 and 350. Please note that this does not mean all intakes are the same throughout the years, there are differences between a 1987 intake and a 1992 intake for example.
All your belt driven accessories, brackets, exhaust, etc... will transer over from the 305 to the 350 without any problems. Once you install the TPI intake on the larger engine, you will need to note the following items that need to be changed. These are the only things you will need to change or worry about to properly convert to a 350:
Injectors
The size of the injectors was a very important difference between 305 and 350 applications. ALL 305 TPI engines came from the factory with 19 lb injectors. ALL 350 TPI engines came from the factory with 22 lb injectors. The Corvettes did not have injectors any larger than the Camaro, as I have people often asking. If you want to use 19 lb injectors on a 350, or 22 lb injectors on a 305, you can, but you MUST have the injector size in the PROM changed. Otherwise, you will run into fueling problems.
Knock Sensor
The knock sensor physically looks the same between the 305 and 350 version, but they do are not the same. This is very important, and should not be overlooked. The knock sensor is responsible for detecting detonation. Detonation produces a specific frequency that travels through the engine block. This frequency is different depending on engine size. In addition, it is important to note that the 350 knock sensors were different between the 85-89 TPI setups and the 90-92 TPI setups. You must use the correct one for your application. The 305 knock sensors were also different between 85-89 and 90-92.
ESC Module
The 85-89 TPI setups used an external ESC module which was mounted by the firewall. This module was different between 305 and 350 engines. Changing this is as simple as disconnecting the 305 module, and plugging in a 350 module. The 90-92 TPI setups did not have an external ESC module. Instead, the ESC circuitry is contained inside the PROM. For this and several other reasons, it is important that you use the correct prom for the engine size you are using.
ECM
Although there were several different ECMs used depending on what year TPI setup you have, the same ECM was used for 305 and 350 engines for a given year. The difference between the engines was the prom. In other words, the 86-89 350 TPI engines used the 1227165 ECM, and so did the 86-89 305 TPI engines. The 90-92 350 TPI F-Body engines (Camaro and Firebird) used the 1227730 ECM, and so did the 90-92 305 TPI engines. The 1985 305 TPI engines used 1226870 ECM, which is the same as the 1985 350 TPI ECM (350 was only available on the Corvette in 1985).
The Corvette used the 1227727 ECM on the 90-91 350 TPI engines. Although the Corvette was never available with a 305, the 1227727 ECM can be used on a 305 if desired.
PROM
This is probably the most important change that needs to be made. Regardless of what ECM you are using, the 305 prom is setup very differently from a 350 prom. Which prom you need will depend on what ECM you use, transmission type, engine size, and a few other details. Contact us if you need help finding the correct PROM for your application.
If you have a 90-92 ECM, and you are having your PROM reprogrammed, you must start with a PROM that was originally for a 350. The 90-92 PROMs have the ESC circuitry onboard, and that cannot be changed.
The 85-89 PROMs can be changed from one engine size to another without worrying about ESC within the PROM, since the module is external on those years.
First of all, the TPI intakes (manifold, plenum, fuel rails, throttle body, runners) were exactly the same between 305 and 350 engines of the same year. There were no differences in these parts whatsoever between one engine size and the other during any year (there were however differences between the intake manifold and fuel rails between the Camaros and Corvettes). For example, a 1987 intake was the same for both a 305 and 350. Please note that this does not mean all intakes are the same throughout the years, there are differences between a 1987 intake and a 1992 intake for example.
All your belt driven accessories, brackets, exhaust, etc... will transer over from the 305 to the 350 without any problems. Once you install the TPI intake on the larger engine, you will need to note the following items that need to be changed. These are the only things you will need to change or worry about to properly convert to a 350:
Injectors
The size of the injectors was a very important difference between 305 and 350 applications. ALL 305 TPI engines came from the factory with 19 lb injectors. ALL 350 TPI engines came from the factory with 22 lb injectors. The Corvettes did not have injectors any larger than the Camaro, as I have people often asking. If you want to use 19 lb injectors on a 350, or 22 lb injectors on a 305, you can, but you MUST have the injector size in the PROM changed. Otherwise, you will run into fueling problems.
Knock Sensor
The knock sensor physically looks the same between the 305 and 350 version, but they do are not the same. This is very important, and should not be overlooked. The knock sensor is responsible for detecting detonation. Detonation produces a specific frequency that travels through the engine block. This frequency is different depending on engine size. In addition, it is important to note that the 350 knock sensors were different between the 85-89 TPI setups and the 90-92 TPI setups. You must use the correct one for your application. The 305 knock sensors were also different between 85-89 and 90-92.
ESC Module
The 85-89 TPI setups used an external ESC module which was mounted by the firewall. This module was different between 305 and 350 engines. Changing this is as simple as disconnecting the 305 module, and plugging in a 350 module. The 90-92 TPI setups did not have an external ESC module. Instead, the ESC circuitry is contained inside the PROM. For this and several other reasons, it is important that you use the correct prom for the engine size you are using.
ECM
Although there were several different ECMs used depending on what year TPI setup you have, the same ECM was used for 305 and 350 engines for a given year. The difference between the engines was the prom. In other words, the 86-89 350 TPI engines used the 1227165 ECM, and so did the 86-89 305 TPI engines. The 90-92 350 TPI F-Body engines (Camaro and Firebird) used the 1227730 ECM, and so did the 90-92 305 TPI engines. The 1985 305 TPI engines used 1226870 ECM, which is the same as the 1985 350 TPI ECM (350 was only available on the Corvette in 1985).
The Corvette used the 1227727 ECM on the 90-91 350 TPI engines. Although the Corvette was never available with a 305, the 1227727 ECM can be used on a 305 if desired.
PROM
This is probably the most important change that needs to be made. Regardless of what ECM you are using, the 305 prom is setup very differently from a 350 prom. Which prom you need will depend on what ECM you use, transmission type, engine size, and a few other details. Contact us if you need help finding the correct PROM for your application.
If you have a 90-92 ECM, and you are having your PROM reprogrammed, you must start with a PROM that was originally for a 350. The 90-92 PROMs have the ESC circuitry onboard, and that cannot be changed.
The 85-89 PROMs can be changed from one engine size to another without worrying about ESC within the PROM, since the module is external on those years.
. I may need to take these instructions into consideration since my IROC is a 305 factory. I just dropped in a 350 block.
11-28-2009, 09:33 PM
#5
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Car: 1988 Pontiac Firebird Formula
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Re: 305 to 350 swap ecm/prom question
Was there a difference from Pontiac to Chevy? I had an 88 Formula, and I don't remember seeing an external esc module......
06-12-2010, 11:42 PM
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Re: 305 to 350 swap ecm/prom question
Here is all the info you need.Troc
305 TPI to 350 TPI Conversion
If you are looking to convert your car from a 305 TPI to a 350 TPI setup, then you should find the information below rather useful. These are all the needed changes to do the conversion.
First of all, the TPI intakes (manifold, plenum, fuel rails, throttle body, runners) were exactly the same between 305 and 350 engines of the same year. There were no differences in these parts whatsoever between one engine size and the other during any year (there were however differences between the intake manifold and fuel rails between the Camaros and Corvettes). For example, a 1987 intake was the same for both a 305 and 350. Please note that this does not mean all intakes are the same throughout the years, there are differences between a 1987 intake and a 1992 intake for example.
All your belt driven accessories, brackets, exhaust, etc... will transer over from the 305 to the 350 without any problems. Once you install the TPI intake on the larger engine, you will need to note the following items that need to be changed. These are the only things you will need to change or worry about to properly convert to a 350:
Injectors
The size of the injectors was a very important difference between 305 and 350 applications. ALL 305 TPI engines came from the factory with 19 lb injectors. ALL 350 TPI engines came from the factory with 22 lb injectors. The Corvettes did not have injectors any larger than the Camaro, as I have people often asking. If you want to use 19 lb injectors on a 350, or 22 lb injectors on a 305, you can, but you MUST have the injector size in the PROM changed. Otherwise, you will run into fueling problems.
Knock Sensor
The knock sensor physically looks the same between the 305 and 350 version, but they do are not the same. This is very important, and should not be overlooked. The knock sensor is responsible for detecting detonation. Detonation produces a specific frequency that travels through the engine block. This frequency is different depending on engine size. In addition, it is important to note that the 350 knock sensors were different between the 85-89 TPI setups and the 90-92 TPI setups. You must use the correct one for your application. The 305 knock sensors were also different between 85-89 and 90-92.
ESC Module
The 85-89 TPI setups used an external ESC module which was mounted by the firewall. This module was different between 305 and 350 engines. Changing this is as simple as disconnecting the 305 module, and plugging in a 350 module. The 90-92 TPI setups did not have an external ESC module. Instead, the ESC circuitry is contained inside the PROM. For this and several other reasons, it is important that you use the correct prom for the engine size you are using.
ECM
Although there were several different ECMs used depending on what year TPI setup you have, the same ECM was used for 305 and 350 engines for a given year. The difference between the engines was the prom. In other words, the 86-89 350 TPI engines used the 1227165 ECM, and so did the 86-89 305 TPI engines. The 90-92 350 TPI F-Body engines (Camaro and Firebird) used the 1227730 ECM, and so did the 90-92 305 TPI engines. The 1985 305 TPI engines used 1226870 ECM, which is the same as the 1985 350 TPI ECM (350 was only available on the Corvette in 1985).
The Corvette used the 1227727 ECM on the 90-91 350 TPI engines. Although the Corvette was never available with a 305, the 1227727 ECM can be used on a 305 if desired.
PROM
This is probably the most important change that needs to be made. Regardless of what ECM you are using, the 305 prom is setup very differently from a 350 prom. Which prom you need will depend on what ECM you use, transmission type, engine size, and a few other details. Contact us if you need help finding the correct PROM for your application.
If you have a 90-92 ECM, and you are having your PROM reprogrammed, you must start with a PROM that was originally for a 350. The 90-92 PROMs have the ESC circuitry onboard, and that cannot be changed.
The 85-89 PROMs can be changed from one engine size to another without worrying about ESC within the PROM, since the module is external on those years.
First of all, the TPI intakes (manifold, plenum, fuel rails, throttle body, runners) were exactly the same between 305 and 350 engines of the same year. There were no differences in these parts whatsoever between one engine size and the other during any year (there were however differences between the intake manifold and fuel rails between the Camaros and Corvettes). For example, a 1987 intake was the same for both a 305 and 350. Please note that this does not mean all intakes are the same throughout the years, there are differences between a 1987 intake and a 1992 intake for example.
All your belt driven accessories, brackets, exhaust, etc... will transer over from the 305 to the 350 without any problems. Once you install the TPI intake on the larger engine, you will need to note the following items that need to be changed. These are the only things you will need to change or worry about to properly convert to a 350:
Injectors
The size of the injectors was a very important difference between 305 and 350 applications. ALL 305 TPI engines came from the factory with 19 lb injectors. ALL 350 TPI engines came from the factory with 22 lb injectors. The Corvettes did not have injectors any larger than the Camaro, as I have people often asking. If you want to use 19 lb injectors on a 350, or 22 lb injectors on a 305, you can, but you MUST have the injector size in the PROM changed. Otherwise, you will run into fueling problems.
Knock Sensor
The knock sensor physically looks the same between the 305 and 350 version, but they do are not the same. This is very important, and should not be overlooked. The knock sensor is responsible for detecting detonation. Detonation produces a specific frequency that travels through the engine block. This frequency is different depending on engine size. In addition, it is important to note that the 350 knock sensors were different between the 85-89 TPI setups and the 90-92 TPI setups. You must use the correct one for your application. The 305 knock sensors were also different between 85-89 and 90-92.
ESC Module
The 85-89 TPI setups used an external ESC module which was mounted by the firewall. This module was different between 305 and 350 engines. Changing this is as simple as disconnecting the 305 module, and plugging in a 350 module. The 90-92 TPI setups did not have an external ESC module. Instead, the ESC circuitry is contained inside the PROM. For this and several other reasons, it is important that you use the correct prom for the engine size you are using.
ECM
Although there were several different ECMs used depending on what year TPI setup you have, the same ECM was used for 305 and 350 engines for a given year. The difference between the engines was the prom. In other words, the 86-89 350 TPI engines used the 1227165 ECM, and so did the 86-89 305 TPI engines. The 90-92 350 TPI F-Body engines (Camaro and Firebird) used the 1227730 ECM, and so did the 90-92 305 TPI engines. The 1985 305 TPI engines used 1226870 ECM, which is the same as the 1985 350 TPI ECM (350 was only available on the Corvette in 1985).
The Corvette used the 1227727 ECM on the 90-91 350 TPI engines. Although the Corvette was never available with a 305, the 1227727 ECM can be used on a 305 if desired.
PROM
This is probably the most important change that needs to be made. Regardless of what ECM you are using, the 305 prom is setup very differently from a 350 prom. Which prom you need will depend on what ECM you use, transmission type, engine size, and a few other details. Contact us if you need help finding the correct PROM for your application.
If you have a 90-92 ECM, and you are having your PROM reprogrammed, you must start with a PROM that was originally for a 350. The 90-92 PROMs have the ESC circuitry onboard, and that cannot be changed.
The 85-89 PROMs can be changed from one engine size to another without worrying about ESC within the PROM, since the module is external on those years.
http://tpiparts.net/305_tpi_to_350_tpi_conversion
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06-13-2010, 12:05 AM
#8
Re: 305 to 350 swap ecm/prom question
Alright...... I dont wanna commit plagerism.
. The info on post #3 was a "control C, and control V" (copy and paste) from the webpage https://www.thirdgen.org/forums/tpi/...-swap-ecm.html (post number 3). So I credit thirdgen.org member T-rock for the info. Careful with what you assume. I did not copy it from TPIParts.net. Im aware of the info from TPIParts.net, not tpiparts.com ( as you mention in your last comment).
I have the website (305-350 conversion from TGO) listed above saved on my desktop and saved as a "favorites" in my menu bar above.
.... Lets not be hostile. We are here to help each other out, not attack or insult others.
. The info on post #3 was a "control C, and control V" (copy and paste) from the webpage https://www.thirdgen.org/forums/tpi/...-swap-ecm.html (post number 3). So I credit thirdgen.org member T-rock for the info. Careful with what you assume. I did not copy it from TPIParts.net. Im aware of the info from TPIParts.net, not tpiparts.com ( as you mention in your last comment).I have the website (305-350 conversion from TGO) listed above saved on my desktop and saved as a "favorites" in my menu bar above.
.... Lets not be hostile. We are here to help each other out, not attack or insult others.
06-13-2010, 01:35 AM
#9
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Re: 305 to 350 swap ecm/prom question
Good way to make friends on here by dragging up old posts and complaining about them after only being a member for a month with just 3 posts to your name
A lot of the valuable info on the forums has been gathered from other sites or sources; amended , modified and probably posted to multiple other forums without credit being given
Last edited by vetteoz; 06-13-2010 at 01:48 AM.
06-14-2010, 10:49 PM
#10
Re: 305 to 350 swap ecm/prom question
You said it vetteoz. I was gonna take the same path and reply with my own comment about him attacking me and being new with 3 posts but I had a conversation with the wise men (TGO moderators and JT) about being hostile. My lesson has been learned. It's funny how many assume without investigating. Oh well, there are bad apples out there.
07-18-2010, 12:32 AM
#11
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Car: 85 Z28 T-Top 36mm sway & wonderbar
Engine: TPI L98 350 W/85 Vette Stage II ECM
Transmission: W/C T-5, alum drive shaft
Axle/Gears: 9 bolt posi, 3:27, PBR's, BB LS1's
Re: 305 to 350 swap ecm/prom question
I agree, A shotty mechanic did the same swap with my son's 85 Z and and practically ruined a new L98 engine. Thanks to this forum, and people like you guys, I'm able to get the kinks out and get it right. I still had the original FJ8 Standard Ignition injectors on this engine. The mechanic lied to my son about putting new injectors in it. I was able to find a 85 Corvette With 4+3 trans ECM for my L98 W/T-5. I recently got some 24lbs Bosch III injectors because in 85 the fuel pressure is 36lb @ idle. The 43.5 is for the 86 on up. The 24lb injector is suppose act like a 22lb @ 36lb FP. The 85 Camaro & Vette TPI's were the only one's with the 36lb fuel pressure. I thought about getting an adjustable regulator cap and going to 43.5 with a set of 22lb injectors, but, down the road I'm considering more HP add-on's.
07-18-2010, 12:43 AM
#12
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Car: 85 Z28 T-Top 36mm sway & wonderbar
Engine: TPI L98 350 W/85 Vette Stage II ECM
Transmission: W/C T-5, alum drive shaft
Axle/Gears: 9 bolt posi, 3:27, PBR's, BB LS1's
Re: 305 to 350 swap ecm/prom question
I hope to have the the car back running with the new injectors this week.
07-19-2010, 04:15 PM
#14
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Car: 85 Z28 T-Top 36mm sway & wonderbar
Engine: TPI L98 350 W/85 Vette Stage II ECM
Transmission: W/C T-5, alum drive shaft
Axle/Gears: 9 bolt posi, 3:27, PBR's, BB LS1's
Re: 305 to 350 swap ecm/prom question
ROGER THAT!!!
07-19-2010, 04:25 PM
#15
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Car: 85 Z28 T-Top 36mm sway & wonderbar
Engine: TPI L98 350 W/85 Vette Stage II ECM
Transmission: W/C T-5, alum drive shaft
Axle/Gears: 9 bolt posi, 3:27, PBR's, BB LS1's
Re: 305 to 350 swap ecm/prom question
I just finished making my order for a BBK-1534 Throttle body and a new IAC housing. I tried to remove the old housing and broke 5 of the torx head bolts. I got so fed up with the old throttle body, I just chucked it aside. It looked horrible anyway. LOL
Grab that sucker out of the trash!!!!!! If your gonna throw it away, send it to me.... Ill pay for the shipping!!!!!!
07-20-2010, 09:50 AM
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07-21-2010, 01:41 AM
#18
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Car: 85 Z28 T-Top 36mm sway & wonderbar
Engine: TPI L98 350 W/85 Vette Stage II ECM
Transmission: W/C T-5, alum drive shaft
Axle/Gears: 9 bolt posi, 3:27, PBR's, BB LS1's
Re: 305 to 350 swap ecm/prom question
Well, I am undecided on what to do with it right now. I have to remove the TPS, IAC and some linkage parts. I tried to remove the IAC housing and its stuck to the throttle body. I hope the BBK works good. I just checked the tracking and it should be here on the 21st. Sometimes it gets so frustrating trying to fix things in 100+ degree weather with high humidity and you have constant setbacks trying to get your ride back on the road. Today I installed an adj fuel pressure reg and two of the six torx screws stripped out. I had to get the Dremmel out and notch them for a flat screwdriver. Get this, nobody around here has these screws. The size is (M 3.5-.6X12). I had to reuse my old ones. This is a bastard size and I may have to tap for the larger M4 screws.
Last edited by 85 ZXX; 08-08-2010 at 05:19 AM.
07-21-2010, 06:56 PM
#19
Re: 305 to 350 swap ecm/prom question
Well, I am undecided on what to do with it right now. I have to remove the TPS, IAC and some linkage parts. I tried to remove the IAC housing and its stuck to the throttle body. I hope the BBK works good. I just checked the tracking and it should be here on the 21st. Sometimes it gets so frustrating trying to fix things in 100+ degree weather with high humidity and you have constant setbacks trying to get your ride back on the road. Today I installed an adj fuel pressure reg and two of the six torx screws stripped out. I had to get the Dremmel out and notch them for a flat screwdriver. Get this, nobody around here has these screws. The size is (M 3.5-.6X12). I had to reuse my old ones. This is a bastard size and I may have to tap for the larger M4 screws.
09-11-2010, 11:33 PM
#25
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Car: 85 Z28 T-Top 36mm sway & wonderbar
Engine: TPI L98 350 W/85 Vette Stage II ECM
Transmission: W/C T-5, alum drive shaft
Axle/Gears: 9 bolt posi, 3:27, PBR's, BB LS1's
Re: 305 to 350 swap ecm/prom question
Thats hard to say, I have a L98 350 in my 85 Z and when it was installed it still had the TPI ECM 305 with 19lb FI. I've read all about changing knock sensor,ESC module, injectors,adj fuel reg,Prom, Cal pack ect. I did all of that and there wasn't much of a difference to justify the expense. I had a dead injector on #7 cyl that was leaking (19lb) that caused a miss so I upgraded to FIC Bosch III injectors (24lb) and went with a BBK 52mm Throttle body and BBK under drive pulleys. In close, my 350 hauled as* with the 305 ECM and 19lb injectors. Its a little faster now with a 350 Vette ECM with the improvements I made.....maybe 25hp increase. Upgrading to a 350 knock sensor and ESC was a waste of money...there was no noticeable difference.
Last edited by 85 ZXX; 09-13-2010 at 02:15 AM.
09-11-2010, 11:39 PM
#26
Re: 305 to 350 swap ecm/prom question
Thats hard to say, I have a L98 350 in my 85 Z and when it was installed it still had the TPI ECM 305 with 19lb FI. I've read all about changing knock sensor,ESC module, injectors,adj fuel reg,Prom, Cal pack ect. I did all of that and there wasn't much of a difference to justify the expense. I had a dead injector on #7 cyl that was leaking (19lb) that caused a miss so I upgraded to FIC Bosch III injectors (22lb) and went with a BBK 52mm Throttle body and BBK under drive pulleys. In close, my 350 hauled as* with the 305 ECM and 19lb injectors. Its a little faster now with a 350 Vette ECM with the improvements I made.....maybe 25hp increase. Upgrading to a 350 knock sensor and ESC was a waste of money...there was no noticeable difference.
09-11-2010, 11:47 PM
#27
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Car: 85 Z28 T-Top 36mm sway & wonderbar
Engine: TPI L98 350 W/85 Vette Stage II ECM
Transmission: W/C T-5, alum drive shaft
Axle/Gears: 9 bolt posi, 3:27, PBR's, BB LS1's
Re: 305 to 350 swap ecm/prom question
Do you still have the 305 ecm in your Iroc?
09-12-2010, 12:01 AM
#28
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Car: 85 Z28 T-Top 36mm sway & wonderbar
Engine: TPI L98 350 W/85 Vette Stage II ECM
Transmission: W/C T-5, alum drive shaft
Axle/Gears: 9 bolt posi, 3:27, PBR's, BB LS1's
Re: 305 to 350 swap ecm/prom question
Up grading to a 350 knock sensor is a great investment. It will not make any performance better. All that it does is "hear" the different frequencies that a 350 does compaired to a 305 block when it's pinging. If it hears that frequency, it'll tell the ECm to back off on the advance spark know as "spark retard." Im sure that you would love for your engine to last right? You do know the dangers of detonation right? So off hand, its not a waste of money. A waste of money would be leaving in your 305 knock sensor, never notice any detonation, and destroy the block. you dont have to hear it to know that your engine in detonating. Most of the time you'll never hear engine knock.
It lasted 4 years with the 305 knock sensor and ESC and still going strong since I upgraded about 2 months ago. I understand what you are saying,,,If you are going to upgrade to a larger displacement engine...do it correctly. Cost my be a huge factor in deciding what is to be done. replacing those two items is around $100.
09-12-2010, 12:07 AM
#29
Re: 305 to 350 swap ecm/prom question
My ECM is the 1227165, which is used in numerous GM cars such as Astro vans, Cavaliers, 86 IROC's and Corvettes. What makes the difference is the MemCal. The PROM on the MemCal is what stores all the vital tables which monitor and control the spark and fuel.
09-12-2010, 12:14 AM
#30
Re: 305 to 350 swap ecm/prom question
Yup. It gets pricey. In my IROC right now is my 305 MemCal. But I bypassed the 305 PROM by using a Moates chipboard and had a blank EPROM programmed by a fellow thirdgen member. Here is the Moates board with the programmed EPROM... http://www.youtube.com/watch?v=qO5YZvWS8I8
This is a OEM MemCal attached to a board similar to the Moates board.
This one is a JET product.
This one is the Moates board
This is a OEM MemCal attached to a board similar to the Moates board.
This one is a JET product.
This one is the Moates board
09-12-2010, 01:12 AM
#31
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Car: 85 Z28 T-Top 36mm sway & wonderbar
Engine: TPI L98 350 W/85 Vette Stage II ECM
Transmission: W/C T-5, alum drive shaft
Axle/Gears: 9 bolt posi, 3:27, PBR's, BB LS1's
Re: 305 to 350 swap ecm/prom question
I have the 1226870 which you know as the "Slow one". I have the cal-pack chip and prom from a 85 Vette 4+3. The 305 and 350 ECM motherboards are the identical. It just has a slow baud rate of 128. The cal-pack has the information to run the engine in open loop or limp mode. Prom is for closed loop.
09-12-2010, 01:20 AM
#32
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Car: 85 Z28 T-Top 36mm sway & wonderbar
Engine: TPI L98 350 W/85 Vette Stage II ECM
Transmission: W/C T-5, alum drive shaft
Axle/Gears: 9 bolt posi, 3:27, PBR's, BB LS1's
Re: 305 to 350 swap ecm/prom question
When I get rid of my setup I'll be going to this; http://www.jegs.com/i/Painless+Perfo...-1#moreDetails
09-12-2010, 05:21 PM
#34
Re: 305 to 350 swap ecm/prom question
Ok. Im gonna need the ECM number, Engine size, and year of the TPI system mainly because of the vats, speed density and such. Or better yet, go here ( http://chevythunder.com/prom_bcc_1989.htm ) and find the PROM ID that you want programmed onto a blank EPROM. Then go here and buy this part ( http://www.moates.net/g1-memory-adap....html?cPath=64 ).
Once you find the PROM ID that will suit your needs, go the the link (shown on the picture) and register for free to access the bank of bin files. Once you find the bin file that you want, download it to you desktop. Then contack my good friend Dan ( https://www.thirdgen.org/forums/member.php?u=97604 ) and ask him if he can program a blank EPROM with the bin file that you just downloaded.)
If you have anymore questions, dont hesitate. I will help you out as much as possible.
As for a 350 knock sensor, here is the cheapest one that I can find for you,,, http://www.rockauto.com/catalog/rafr...580458-4616697
Once you find the PROM ID that will suit your needs, go the the link (shown on the picture) and register for free to access the bank of bin files. Once you find the bin file that you want, download it to you desktop. Then contack my good friend Dan ( https://www.thirdgen.org/forums/member.php?u=97604 ) and ask him if he can program a blank EPROM with the bin file that you just downloaded.)
If you have anymore questions, dont hesitate. I will help you out as much as possible.
As for a 350 knock sensor, here is the cheapest one that I can find for you,,, http://www.rockauto.com/catalog/rafr...580458-4616697
09-13-2010, 09:50 PM
#37
Re: 305 to 350 swap ecm/prom question
Depends. You would want to stay strickly 305 with 305 and 350 with 350. So if you need the 350 knock sensor for your 91 350, then yes. The detonation between the 305 and 350 is different in frequency. Go to Rockauto.com and punch in your info to get the prices. If you decide to stay with the 305, then my friend should be able to do the programming of the blank EPROM. Is your aftermarket cam "Computer-Controlled?" i ask because in certain years (which differ from being MAF or speed density) the MAF will self adjust itself to the load, air intake, and temperatures and cam (aslong as the cam is not to radical). The MAF system needs vacuum. thats how our TPI work. If the lift on the cam is too high, the engine loses vacuum. Then the ECM reads the loss of vacuum and tries to adjust its self which will send bad timing and incorrect fuel amounts. In other words, you'll getting very horrible idling and stalling (if the car turns on). Now for Speed Density, the PROM is "hard programmed" and uses tables and makes adjustments soley on engine load, not amount of air intake, air temp, ect. As for the 24 lb injectors, that can easily be changed in a program prior to programming. Just contact Dan and tell him what you need and got and Im sure he'll have an answer for you.
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