Increasing mid range power

The MaDDeSTMaN · 24-05-2005, 10:06 PM

I was just wondering, what modifications would be best for increasing mid-range (2500rpm to 5000rpm) power and torque.

I thought about posting this in the Escort or the 4 cyl sections, seeing as I am specifically interested in boosting the power that my 2L OHC Pinto in my Escort makes, but then I realised that the methods to achieve this increase would probably be similar for most engines.

I know, it may seem stupid to some people, seeing as I'm talking about an engine that can rev to 6 grand and beyond without trouble, but I'm not interested in revving the rings out of my engine, and an increase in power and torque lower in the rev range would be much more useful in day to day driving, I'm not after ultimate power, and I want to keep low rev drivablility as much as possible, and I don't want fuel economy to suffer drastically.

I'm guessing getting a aftermarket cam designed to work best at those sort of revs would be a good start (one designed for towing with an auto, so setup for good torque low in the revs, for example), but what else would help, and am I wrong with that idea of the cam? What sort of extractors would help (4-2-1 or 4-1) or would the stock exhaust be better? I'm guessing there woul dbe no real need for changing the carby, but am I wrong?

Finally, would I be better off going for more traditional modifications and getting it working better higher in the revs and sacrificing low rev driveability.

Thanks.

Steffo · 24-05-2005, 10:55 PM

You could also stroke it. Ford made a 2.3litre version of that engine, which powered Fox-Body Mustang's in the 1980's. There was also an SVO, not sure if it was turbo stock or not (I think it was).. but I know of quite a few 750 odd hp 9 sec Fox-Bodies in the 'states using it. But yeah, generally, longer stroke = less revs and more low end/mid range torque.

25-05-2005, 02:13 AM

Best place to start generally is the exhaust, ( this you can do yourself) a good set of extractors, add a two inch exhaust with a free flow muffler.

Next a mild head, either change over or have your own done, this should include the cam and specify you want mid range torque.

These mods will give you what you want without breaking the bank and most likely improve your fuel economy (depending on how you drive)

Regards Prof. Rabbit

The MaDDeSTMaN · 25-05-2005, 09:21 AM

Quote:

Originally Posted by prabbit

Best place to start generally is the exhaust, ( this you can do yourself) a good set of extractors, add a two inch exhaust with a free flow muffler.

Next a mild head, either change over or have your own done, this should include the cam and specify you want mid range torque.

These mods will give you what you want without breaking the bank and most likely improve your fuel economy (depending on how you drive)

Regards Prof. Rabbit

Ahh, cool, so it would be worth getting a good set of extractors and a good exhaust. Ok, two questions, would it make any difference what setup (4-2-1 or 4-1) the extractors are, and what are the chances of getting that annoying drone sound at freeway speeds (~3000rpm) with a two inch exhaust and free flow muffler?

Regarding the head, do you mean to get it mildly ported? Polishing isn't as important as a little roughness isn't always a bad thing according to the book I have on modifying the OHC by David Vizard, would you agree, or is that more important if the revs are being taken higher on a regular basis?

Sounds like what I want is achieveable without spending a small fortune, and if it improves fuel economy, then I'll be more then happy! My driving style (when it comes to when I shift gears) is perhaps more suited to a Falcon then an Escort - I generally shift up somewhere between 2000 and 2500rpm, and generally the only time it reaches 3000rpm is when I'm driving on a freeway, which is of course because it's only got the stock 4 speed in it - one day I plan on putting a 5 speed box in. It doesn't often get much in the way of throttle either - I'd say usually no more then 1/3rd of full throttle. Of course, if I need quicker acceleration (going for a gap in peak hour traffic, for example) I'll let it rev harder and give it more throttle, but the tacho very rarely sees above 4000rpm - I don't like to rev the rings out of my engine (even though it sounds tough above 3500rpm).

So given that driving pattern, which I think is already a fairly economical way of driving already, after making those changes I should get better fuel economy, seeing as on the occasions where I actually give it a bit more throttle and let it rev out a bit more, I won't have to give it as much throttle or let it rev as hard as I have to now. And would I be right in suspecting that making those changes would actually be improving the efficiency of the engine?

Steffo, yeah, I could stroke it, and I'm not ruling that out, but that sounds much more expensive and time consuming then porting the head, getting an after market cam and a good exhaust setup. Although, having said that, I could always do the cam, head and exhaust first, then stroke it later - with all that done, I'm sure it would be much nicer to drive then a stocker...

Ok, final question (for now, lol), could I do it one bit at a time? Say get the extractors and exhaust done first, then later on get the cam (and associated bits) done, then later on have the head pulled off to have it ported? If so, which mod would make the most sense to do first (I'm thinking extractors and exhaust, but I could be wrong)?

rag top · 25-05-2005, 03:59 PM

For the exhaust, go the 4-2-1's. better mid range. I thought that 4-1's was more for top end power.

Do the exhaust first, and see how you like that. Then do the cam...

Also, what air filter setup are you running? I found that by changing to an open element setup, it seemed a bit more responsive.

The MaDDeSTMaN · 25-05-2005, 08:58 PM

Quote:

Originally Posted by '67

For the exhaust, go the 4-2-1's. better mid range. I thought that 4-1's was more for top end power.

Do the exhaust first, and see how you like that. Then do the cam...

Also, what air filter setup are you running? I found that by changing to an open element setup, it seemed a bit more responsive.

Cool, thanks for that, 4-2-1, I thought they would be the better option, but wanted a second opinion first. I'll have to do the extractors and exhaust at the same time won't I? Or would the extractors be no problem to bolt up to the standard exhaust pipe?

Right now, it's still running the stock air filter, on top of the stock carby. Where would be the best place to get an open element setup from, and how much would it set me back? Sounds like a good idea to me. Did it change the sound of the engine at all, I'm thinking because there would be less to muffle the induction sound, it would be slightly louder, which is fine by me - I love the sound of that engine.

Which reminds me, with an open element air filter setup, extractors and a decent exhaust, how loud would the car end up being, and would it have trouble passing the EPA noise test? I don't mind it being loud, as long as it's not so loud that it fails the EPA test.

rag top · 26-05-2005, 08:57 AM

The open element air filter will give you a bit more induction noise. They should be available from any decent automotive parts retailer. I haven't bought one in a while, but I'd expect it to cost around the $40ish mark.

I'd do the extractors and the exhaust at the same time. The flange from the standard system won't bolt up to the extractors as they are in different spots. The cost of getting the extractors mated up to the standard system, you may as well put towards the new system and get it all done at the same time.

As for noise, depends on your exhaust setup... Decent muffler, should be okay. If it is too loud, then add a hotdog.

mik · 27-05-2005, 12:29 AM

how about a supercharger off a 2litre toyota, cost from a wreckers about 350/400 buks, belt driven cheap horsepower might be worth a go , dont no about economy, but gotta be more ponys

The MaDDeSTMaN · 28-05-2005, 10:27 AM

Quote:

Originally Posted by '67

The open element air filter will give you a bit more induction noise. They should be available from any decent automotive parts retailer. I haven't bought one in a while, but I'd expect it to cost around the $40ish mark.

I'd do the extractors and the exhaust at the same time. The flange from the standard system won't bolt up to the extractors as they are in different spots. The cost of getting the extractors mated up to the standard system, you may as well put towards the new system and get it all done at the same time.

As for noise, depends on your exhaust setup... Decent muffler, should be okay. If it is too loud, then add a hotdog.

Ahh, ok, thanks for that. I suspected that I'd have to do the entire exhaust system at the same time as the extractors, oh well, so be it. Should be worth it anyway.

Pity the standard exhaust that is on it now is pretty much new and it'd mean removing a perfectly good exhaust.

Regarding the open element air filter, if I have to pop the hood for the boys in blue, are they likely to give me any grief if I've got one of those? Not that it's any real problem, I could always just put the standard air filter setup back on, but I could do without the hassle if they're going to have a problem with it.

I think I might go with the hot dog to start with, just to be on the safe side - I don't mind it being loud, but I don't want it to be so loud I can't drive it without getting pulled over - we are talking about my daily driver here.

Quote:

Originally Posted by mik

how about a supercharger off a 2litre toyota, cost from a wreckers about 350/400 buks, belt driven cheap horsepower might be worth a go , dont no about economy, but gotta be more ponys

Wouldn't I have to make sure my engine is setup for forced induction then, regarding compression etc? Also, seeing as I'm still on my Ps and the car weighs less then 1000kgs, I have to make sure I don't put it over the power limit, not that it's enforced too well, but knowing my luck...

Besides, I can just imagine the look on a policemans face if I popped the hood and he saw a supercharger bolted on there... but maybe that's an idea for the future, along with stroking it... :eclipsee_

rag top · 28-05-2005, 03:36 PM

Quote:

Originally Posted by The MaDDeSTMaN

Regarding the open element air filter, if I have to pop the hood for the boys in blue, are they likely to give me any grief if I've got one of those? Not that it's any real problem, I could always just put the standard air filter setup back on, but I could do without the hassle if they're going to have a problem with it.

I have never had any problems with running the open element air filter, just make sure that everything is connected (pollution gear, oil breather, etc).
You could also make it look like it belongs there by painting the top and base the same colour as the rocker cover.

30-05-2005, 03:41 AM

Yes you will need to do the complete exhaust for the greatest benefit, don't get talked into a mega bucks job you can stick a football into, talk to a couple of professionals about the job and if you feel happy about using a set of spanners buy the parts and fit it yourself.

The "sound" can be matched to your requirments, just ask for a quiet system, no exhaust "needs" to be loud to be efficent.

Regards Prof. Rabbit

Quote:

Originally Posted by The MaDDeSTMaN

Ahh, ok, thanks for that. I suspected that I'd have to do the entire exhaust system at the same time as the extractors, oh well, so be it. Should be worth it anyway.

Pity the standard exhaust that is on it now is pretty much new and it'd mean removing a perfectly good exhaust.
:eclipsee_