1.7L SOHC Non-Vtec Swap
01-30-2023
#62
Re: 1.7L SOHC Non-Vtec Swap to Vtec
Ok I'm finding out more stuff about this Non-Vtec to Vtec. Do I need to change out any of my wiring inside my car? Like body harness which is inside my glove box. Once again my car which is a Lx now installed a Vtec motor. I have computer for it and harness that plugs into all but do I need to change my wiring from Inside like the Ob2 wiring or anything to help me save time.
01-31-2023
#63
Super Moderator
Join Date: Jun 2012
Location: Ohio
Age: 31
Posts: 4,728
Received 1,865 Likes
on
1,311 Posts
Rep Power: 196 
02-19-2023
#64
Registered!!
Join Date: Feb 2023
Location: Boston
Age: 33
Posts: 7
Received 0 Likes
on
0 Posts
Rep Power: 0 
Re: 1.7L SOHC Non-Vtec Swap
should be possible - the ecu will not know the vtec is there.
Mac, just to correct, the block also have oil squirters to the pistons and slightly higher compression compared to the non-VTEC engine.
not sure of the differences in the camshaft profiles, though...
what will happen is that one of the exhaust valves will most likely not open (almost) since it is what the VTEC will activate, so it will be a 3-valve engine instead of 4-valve. More low end torque but no power in higher end.
Mac, just to correct, the block also have oil squirters to the pistons and slightly higher compression compared to the non-VTEC engine.
not sure of the differences in the camshaft profiles, though...
what will happen is that one of the exhaust valves will most likely not open (almost) since it is what the VTEC will activate, so it will be a 3-valve engine instead of 4-valve. More low end torque but no power in higher end.
02-20-2023
#65
Registered!!
Join Date: Feb 2023
Location: Boston
Age: 33
Posts: 7
Received 0 Likes
on
0 Posts
Rep Power: 0 Re: 1.7L SOHC Non-Vtec Swap
I too am doing the D17a1 to D17a2 swap. The D17a1 thru a rod bearing. I have a full door SI civic that can no longer be registered. I need some clarification.
I have the a2 installed and running off the a1 computer. The car still has the lx exhaust and computer. The car runs.... just not as good as it should.
I need to finish the a1 to a2 swap.
I will be using the donor SI computer and ignition key. Will this avoid having to flash the computer?
Will be using the SI engine harness to replace the LX harness so it vtec can plugged in.
Will be using the full SI exhaust with its 02 sensors. Front 02 sensor should be ok.
Will the only issue be the 02 sensor in the cat? The SI exhaust has the cat under the car rather than by the manifold in the front of the car. There is no place to plug this in once the engine harness is replaced with the SI harness. This 02 sensor is plugged into a different harness on the SI. How can this issue be addressed?
I have the a2 installed and running off the a1 computer. The car still has the lx exhaust and computer. The car runs.... just not as good as it should.
I need to finish the a1 to a2 swap.
I will be using the donor SI computer and ignition key. Will this avoid having to flash the computer?
Will be using the SI engine harness to replace the LX harness so it vtec can plugged in.
Will be using the full SI exhaust with its 02 sensors. Front 02 sensor should be ok.
Will the only issue be the 02 sensor in the cat? The SI exhaust has the cat under the car rather than by the manifold in the front of the car. There is no place to plug this in once the engine harness is replaced with the SI harness. This 02 sensor is plugged into a different harness on the SI. How can this issue be addressed?
02-20-2023
#66
Registered!!
Join Date: Feb 2023
Location: Boston
Age: 33
Posts: 7
Received 0 Likes
on
0 Posts
Rep Power: 0 Re: 1.7L SOHC Non-Vtec Swap
should be possible - the ecu will not know the vtec is there.
Mac, just to correct, the block also have oil squirters to the pistons and slightly higher compression compared to the non-VTEC engine.
not sure of the differences in the camshaft profiles, though...
what will happen is that one of the exhaust valves will most likely not open (almost) since it is what the VTEC will activate, so it will be a 3-valve engine instead of 4-valve. More low end torque but no power in higher end.
Mac, just to correct, the block also have oil squirters to the pistons and slightly higher compression compared to the non-VTEC engine.
not sure of the differences in the camshaft profiles, though...
what will happen is that one of the exhaust valves will most likely not open (almost) since it is what the VTEC will activate, so it will be a 3-valve engine instead of 4-valve. More low end torque but no power in higher end.
02-21-2023
#67
PITA Admin
Administrator
iTrader: (1)
Join Date: Dec 2008
Location: TN
Age: 52
Posts: 14,791
Received 1,447 Likes
on
1,202 Posts
Rep Power: 338 
The following users liked this post:
Colin42 (02-21-2023)
02-21-2023
#68
Registered!!
Join Date: Feb 2023
Location: Boston
Age: 33
Posts: 7
Received 0 Likes
on
0 Posts
Rep Power: 0 Re: 1.7L SOHC Non-Vtec Swap
02-22-2023
#69
PITA Admin
Administrator
iTrader: (1)
Join Date: Dec 2008
Location: TN
Age: 52
Posts: 14,791
Received 1,447 Likes
on
1,202 Posts
Rep Power: 338 Re: 1.7L SOHC Non-Vtec Swap
apexii vafc2 have a VTEC controller.
without an EX ECU or the apexii vafc2, the VTEC is just dead weight
regardless, the VTEC in these cars are VTEC-E
don't be too excited about it
https://www.civicforums.com/forums/3...iscussion.html
without an EX ECU or the apexii vafc2, the VTEC is just dead weight
regardless, the VTEC in these cars are VTEC-E
don't be too excited about it
https://www.civicforums.com/forums/3...iscussion.html
02-22-2023
#70
Registered!!
Join Date: Feb 2023
Location: Boston
Age: 33
Posts: 7
Received 0 Likes
on
0 Posts
Rep Power: 0 Re: 1.7L SOHC Non-Vtec Swap
apexii vafc2 have a VTEC controller.
without an EX ECU or the apexii vafc2, the VTEC is just dead weight
regardless, the VTEC in these cars are VTEC-E
don't be too excited about it
https://www.civicforums.com/forums/3...iscussion.html
without an EX ECU or the apexii vafc2, the VTEC is just dead weight
regardless, the VTEC in these cars are VTEC-E
don't be too excited about it
https://www.civicforums.com/forums/3...iscussion.html
02-22-2023
#71
PITA Admin
Administrator
iTrader: (1)
Join Date: Dec 2008
Location: TN
Age: 52
Posts: 14,791
Received 1,447 Likes
on
1,202 Posts
Rep Power: 338 Re: 1.7L SOHC Non-Vtec Swap
the controller is the brains.
Can your body move without a head?
Therefore, the VTEC will just be dead weight.
Also, due to the design of the VTEC-E, the breathing in higher RPM will be hampered.
Can your body move without a head?
Therefore, the VTEC will just be dead weight.
Also, due to the design of the VTEC-E, the breathing in higher RPM will be hampered.
- A non-VTEC will be using all 4 valves all the time, but will not have as much torque in lower RPM and not as much HP in higher RPM compared to having the VTEC working.
- A VTEC engine with non-working VTEC will act normal in lower RPM, but hampered at higher RPM, probably worse than a non-VTEC engine - not tuned for it
The following users liked this post:
Colin42 (02-22-2023)
Thread
Thread Starter
Honda Civic Forum
Replies
Last Post
ItsjustKenny
SOHC D17Ax non-VTEC - VTEC Engine Swaps
3
05-17-2019 10:49 AM
310civicEX
Mechanical Problems/Vehicle Issues and Fix-it Forum
2
10-22-2017 07:58 PM
Dewaholic
1st - 5th Generation Civic 1973 - 1995
5
05-03-2010 01:46 PM
