Ok I found some reciepts today and written on one was my gas mileage prior to my DOHC PCM swap, the results were astonishing! My best Tank of Gas ever in the Neon was 280 Miles, My best tank with DOHC PCM was 215 miles, I took my plugs out and they are blacker than Jessie Jackson.

The DOHC PCM does add power with other mods done to your car such as Turbo or high compression, but with a mostly stock engine it will load up the pistons and plugswith un used gas and you have to rev it up once in a while or it loads up, I really took notice today and I can almost watch the gauge to see it sucking the gas. I'll drive 20 miles and its dropped a quarter of an inch or more and I guess now its just really festered me to the point where I'm throwing the stock SOHCPCM on again especially after seeing gas at $3.19 a Gallon, just kinda really pissed me off. Why can't we go take some oil fields over in Iran or Saudi Arabiaso gas can be $1 a gallon! and so us American's can fill our gas guzzling SUV's and Muscle Cars up.

I still may put the DOHC PCM back ononce I finnish up my Turbo manifold this week but for now and if I don't have any problems when turbo is on the SOHC pcm is staying on. The 5hp and waste of gas isn't worth it on a stock SOHC, especially once it loads up with gas your losing power as the day goes by in stop 'n go traffic. The power it gives is good when racing but its not as responsive once you ***** foot around town all day then need it to kick in.

I recomend that unless you have a turbo or some sort of internal engine mods or high output ignition system it probably doesn't pay to have a DOHC PCM.

 

Pretty interesting. Thanks for the heads up.

 

I got the SOHC PCM back in and it was responsive again! I got on the highway and did 90mph and when I got off the ramp it actually had ***** still, usually with the DOHC PCM I'd get of off the highway and it would sound like it wanted to puke and kinda have a little lag on the pedal. Well no more its running great!.

 

if i remember correctly....there were alot of people on this forum that said it wasnt a good idea to swap it (me being one of them) now we just have more proof as to why for those who dont wanna listen

 

I know I waved the DOHC pcm's flag for a while and it did help me the dyno numbers were therebut if your not clearing out the carbon every few hours of drivingit will make the car into a slouch and its just too much babysittingfor aminimal gain plus itsgas consumption vs the stock SOHC pcm is just another reason why its not needed on a mostly stock engine.

IfI had a far from stock Engine I'd probably go back to the DOHC pcmbecause then I'd have mods that support it, With the turbo it might actually be a good combo but with a stock engine its actually shooting yourself in the foot.

I did a recent Dyno run on my G-Tech and I got 108 Hp to the wheels, whenI first had the DOHC pcm on I got a instant 5hp gain over my baseline figure of 114hp, My current numbers afterswapping back to stock is116hp (I have the header on since old baseline, probably where the 2hpgain comes in). My torque curve feels alot more sturdy but off the line is the only thing I'm not sure about if its decreased or increased or stayed the same, I never really looked at the G-tech while I was accellerating, But I will go test and post the numberssoon : )

 

Funny, because on a REAL dyno (like the one Cory (owner of Modern Performance) uses) he saw a loss in power by putting a DOHC PCM on a SOHC engine because it runs too rich.

 

my gtech reported wheel hp at 108 a loss from my previos 114hp with the dohc pcm running rich, clean the carbon out and watch the gain, only temporary gains but gains none the less. You gota admit the gtech is in the ball park at least.

1 thing that could have affected my results were the fact I did most of the test within the first half hour of the car running rather than after 2 hours of running like I did yesterday.within 30minutesof going it was a 5hp imporvment over the stock pcm but as the day wore on it dogged down to 108hp un like the SOHC pcm whichstayed within 1-2hp from the cold start temp 2 hours later. With the DOHC PCM the results are losses unless you give it a good rev after being driven conservativly. Bottum line the SOHC pcm is more consistant.

I do notice that I can't churp the tires with half throttle anymore since installing the stock Sohc PCM, but in turn Rpm responce was much better at 2,000+ Rpm. Under a load the car responds better too with the stock pcm.