Honda VX engine not performing, why???
 

I've just done an engine swap in my '95 Civic and put in a VX (VTEC-E) engine and I'm missing something because I'm not getting any better gas mileage than my 450,000kms, old, stock, 16V, single overhead cam that I swapped out???
I've put in new spark plugs, distributor cap, air filter, oil change. What am I missing?:confused:

Re: Honda VX engine not performing, why???
 

Are you using the FED VX ECU? It will put the engine into lean burn under certain conditions. The CAL VX ECU does not have lean burn capabilities.

Re: Honda VX engine not performing, why???
 

Honestly I'm not sure, I bought it at TorontoJDM and the engine is from Japan, it's single stage that kicks in at 5,000rpm, I think it's a D15B1, it says VTEC-E on the head.

Re: Honda VX engine not performing, why???
 

do you have the transmission that came with the car or do you have the VX transmission? The 2001-2005 Civics with Vtec (EX) only see a marginal improvement (2mpg avg increase) over the older vtec (96-00 EX) and no increase over the non vtec (DX/LX). Yes I am aware the EX has a slightly closer transmission than the DX/LX but when you compare the EX from '96 and the EX from '02 (best years), there you can see the mileage improvement. I would suppose if you coupled the newer vtec version with a DX/LX transmission, you'd see a marginal improvement in fuel economy but no VX territory. The VTEC in the 2001-2005 Civic EX is very similar to the VTEC in the 92-'95 VX and '96-'00 HX (12 valves low, 16 valves high). The primary reason to go with the vtec in the VX is because it adds low end torque which goes nicely with the "tall" CX/VX transmission and therefore adds fuel economy.

Re: Honda VX engine not performing, why???
 

I have the stock '95 CX 5 speed transmission, it turns at 2,500 rpm at 55-60 miles an hour which I mostly travel at on my commute.

Re: Honda VX engine not performing, why???
 

I've found that I should have a 5 wire oxygen sensor and I have a 4 wire. Also they put a non-stock 4 into 2 exhaust manifold. It sounds like it makes a big difference so I'm going to try and find the stock manifold and 5 wire O2 sensor.

Re: Honda VX engine not performing, why???
 

lulz... A CX transmission does NOT turn at 2500 rpm at 55-60mph.. THATS THE DX/LX/(1996-2000 CX)TRANSMISSION! If you really had a '92-'95 CX/VX transmission, you'd be going around 74mph at 2500rpm vs the current 59mph..

https://www.fatboyraceworks.com/gears...raph&Compare=1

Re: Honda VX engine not performing, why???
 

you don't need a 5 wire for a D15B1.. You need to reconfirm again what exactly you have. I can't believe you knew enough to install an engine but not enough to actually know what the hell you installed.

Re: Honda VX engine not performing, why???
 

Ok I have Montegi MR7 16" wheels with 205/45 tires. About knowing "what the hell" I installed, it says VTEC-E on the valve cover and yes I'm trusting it is, how can I tell if if really is VTEC-E?

Re: Honda VX engine not performing, why???
 

Prolly is a VTEC-E but the VTEC-E is not a D15B1, it's a D15Z1.

Correct wheel size and transmission should help you with the mpg numbers, along with the correct expensive 5 wire o2 sensor. No surprised you are not getting better numbers with the current setup you have (high revving tranny and big wheels). If you can, get yourself a set of the original VX wheels on craigslist and put Vredestein Quatrac 2 tires on them 165/70/13. https://www.vredestein.com/

VX wheels