Mopar 98 Sohc computer

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CbBlackVr4
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Mopar 98 Sohc computer

Post by CbBlackVr4 » Tue Aug 12, 2008 1:26 pm

what differences in power and fuel economy do you see over stock???

i really want to get this to boost power a bit but dont want it to hurt fuel economy

thanks for the help
91 galant vr4 (race car)
98 dodge neon sohc sedan (daily)

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fusion210
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Post by fusion210 » Tue Aug 12, 2008 6:12 pm

Here's the sport compact car dyno of a mopar dohc pcm on a sohc with a few bolt ons.
http://www.sportcompactcarweb.com/proje ... to_14.html

Pretty good gains down low, that little loss at higher rpms won't matter too much if you won't be revving that high, obviously.

As far as a sohc mopar pcm, I'm not sure, but I imagine it would be similar.

You could always dyno test it. :)

As far as fuel economy, it won't turn it into a gas hog, but you will have to use premium grade gas.

CbBlackVr4
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Post by CbBlackVr4 » Tue Aug 12, 2008 11:03 pm

that doesnt tell me anything about what i asked though... it just says dohc ecu... im wanting to put a mopar sohc ecu on my car not a sohc..

thanks though
91 galant vr4 (race car)
98 dodge neon sohc sedan (daily)

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fusion210
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Post by fusion210 » Thu Aug 14, 2008 3:35 am

It's not just a dohc pcm, it's a mopar performance reprogrammed one.

I understand what you want perfectly. The problem is that in all my years I've never seen a dyno test of one vs the oem pcm. So I don't think you're going to find one.

What we do have is that dyno and the understanding that there isn't going to be a huge difference. They talk about it more in the article. http://www.sportcompactcarweb.com/proje ... index.html

I have an oem dohc pcm on my near stock sohc beater and a sohc af/x reprogrammed one on my 2.0l dohc. It's not a big deal.

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Post by BlueR/T » Thu Aug 14, 2008 3:50 am

your still not getting it, he's wondering if a MPP PCM has a big power difference

the Mopar PCM is a huge advantage racing because of the higher rev limiter, however power increases are not noticeable, but nothing less then a 20HP increase would be

stock increase is ~8 HP, if you have an intake, header, exhaust its ~12 hp

yes your mileage will go down a little, (2-3 MPG) but the real painfull part is that you need to run premium 92+ (91 at higher elevations)

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Post by CbBlackVr4 » Thu Aug 14, 2008 11:59 am

y wouldnt i buy a sohc pcm for my sohc... doesnt make sense to buy a dohs pcm for a sohc

im not wanting a race car here i just want a little faster with still keeping great fuel economy
91 galant vr4 (race car)
98 dodge neon sohc sedan (daily)

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Post by BlueR/T » Thu Aug 14, 2008 2:04 pm

The Mopar PCM comes in a SOHC version, why would you get a DOHC one?

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fusion210
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Post by fusion210 » Thu Aug 14, 2008 6:04 pm

I'm not trying to be mean here or anything, just clear and to the point.
BlueR/T wrote:your still not getting it, he's wondering if a MPP PCM has a big power difference
Which is why I posted a dyno test of one. Otherwise you're just stuck with manufacturer claims which don't always live up to their promise. Testing at the dragstrip also isn't a great way to test a power increase since you'll also see an improvement in raising your shift points, not from a power increase.
BlueR/T wrote: the Mopar PCM is a huge advantage racing because of the higher rev limiter, however power increases are not noticeable, but nothing less then a 20HP increase would be
Gains less than 20 horsepower are noticeable for sure. I have had one sohc mopar performance pcm and five different af/x pcms. I've tested the af/x pcm at the dragstrip and the mopar vs the af/x at the dragstrip.
BlueR/T wrote: stock increase is ~8 HP, if you have an intake, header, exhaust its ~12 hp
Peak horsepower is worthless other than bragging rights. At what rpm did you gain 8-12 horsepower? Where are you getting this information? Show me your proof please.
BlueR/T wrote: yes your mileage will go down a little, (2-3 MPG) but the real painfull part is that you need to run premium 92+ (91 at higher elevations)
Again, show me your proof where you drove exactly the same on the same trips.

I'd bank on you having no proof and just regurgitating info or making it up. That's the problem with the internet. Just copying manufacturer's claims and second/third hand information made from reading other posts that may or may not have factual information.
CbBlackVr4 wrote:y wouldnt i buy a sohc pcm for my sohc... doesnt make sense to buy a dohs pcm for a sohc
BlueR/T wrote:The Mopar PCM comes in a SOHC version, why would you get a DOHC one?
For everything it said in the article I posted.

Not mentioned in the article... There are more used dohc ones than sohc ones, so it's easier to grab one at a lower price.

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Post by INVUJerry » Sat Nov 01, 2008 5:58 pm

CbBlackVr4 wrote:y wouldnt i buy a sohc pcm for my sohc... doesnt make sense to buy a dohs pcm for a sohc

im not wanting a race car here i just want a little faster with still keeping great fuel economy
I am running a DOHC computer in my 98 SOHC. With bolt ons, and weight redux I ran a 15.4, and got 37 MPG driving daily. I got 45 MPG on long trips.
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Post by BlueR/T » Sun Nov 02, 2008 12:24 am

fusion210 wrote:I'm not trying to be mean here or anything, just clear and to the point.
BlueR/T wrote:your still not getting it, he's wondering if a MPP PCM has a big power difference
Which is why I posted a dyno test of one. Otherwise you're just stuck with manufacturer claims which don't always live up to their promise. Testing at the dragstrip also isn't a great way to test a power increase since you'll also see an improvement in raising your shift points, not from a power increase.
you posted a link to the SCC project neon, they used a stock DOHC PCM not a mopar one
fusion210 wrote:
BlueR/T wrote: the Mopar PCM is a huge advantage racing because of the higher rev limiter, however power increases are not noticeable, but nothing less then a 20HP increase would be
Gains less than 20 horsepower are noticeable for sure. I have had one sohc mopar performance pcm and five different af/x pcms. I've tested the af/x pcm at the dragstrip and the mopar vs the af/x at the dragstrip.
sure they are noticeable, like when you notice how your car runs a tad faster on a cold morning

seriously if you feel a 8 HP increase it's all in your head, things like throttle response and sound are much more noticeable
fusion210 wrote:
BlueR/T wrote: stock increase is ~8 HP, if you have an intake, header, exhaust its ~12 hp
Peak horsepower is worthless other than bragging rights. At what rpm did you gain 8-12 horsepower? Where are you getting this information? Show me your proof please.
a 12 HP increase at say 4000 rpm could mean the difference between staying side-by-side or slightly walking,

even if you never increase your max HP, if you can get there faster you still make your car faster
fusion210 wrote:
BlueR/T wrote: yes your mileage will go down a little, (2-3 MPG) but the real painfull part is that you need to run premium 92+ (91 at higher elevations)
Again, show me your proof where you drove exactly the same on the same trips.
i should have clarified that your city mileage will go down, but mileage mainly depends on driving habit, the MPP runs a little bit richer at WOT then the stock one does, it relies on timing advance to gain HP, not A/F ratio, and since you have the higher rev limiter, you will spend more time in the 6500+ range which eats gas

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Post by INVUJerry » Sun Nov 02, 2008 12:27 am

It runs richer at first, but the LTFT trims it out, so the gas mileage goes up the more and more you drive it.

With just bolt ons on my car (3.0 intake, afx long tube, exhaust, DOHC mopar computer, atx TB) I was still shifting at 6700. It didn't pull any harder after that. Your mileage may vary.
2005 Neon SXT Black - SOLD
1998 Neon Coupe - SOLD
2004 Neon SRT-4 - 13.9@102
1995 Neon ACR NYG Sedan - 12.5:1 SOHC coming
1996 ACR Sedan - Koni yellows, stock as hell
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