Boring Question?

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I was wondering if I bored out my 2.3 liter to a 2.5 liter (like on the newer Rangers 4 cylinders), if thats as much of a bore as I can go? Thunderbird also said something about destroking the motor to increase the revs (which is what I want to achieve), if I destroked her about .015 or .020 would this be sufficient to obtain a noticably higher RPM? Kinda confused over this.
Thanks

posted by  99integra

No. The 2.3 was enlarged to 2.5 by increasing the stroke to 86.5mm. To get your 2.3 up to 2.5 using just an overbore, you'd have to go from a 96mm bore to a 100mm bore. The largest standard oversize pistons available are 97.5mm. If you attempted to bore the block out to 100mm, you would be into the water jackets. Don't work.

More importantly, why do you think you want more RPM? On the street you spend 99.9% of your time below 4k RPM. Increasing the redline would serve no useful purpose and would actually lower performance in the most important part of the rev range.

posted by  vwhobo

So the smartest way to do it is increase the stroke? And I was lookin to get a couple hundred more RPM because I kind of have to floor her when I'm merging onto the highway to get up to speed and I sometimes have to redline her to get to the speed limit when theres that never ending line of cars in Tampa :ohcrap:

posted by  99integra

If you build the engine for more torque, you don't need to scream it to make power. Torque is and always has been king on the street, horsepower is just something that people who want to appear in the know talk about. Let's face it, a little 2.3 dragging around a 3000+ pound vehicle isn't going to set the world on fire without some major work. These folks (http://www.racerwalsh.com/category/4cylinder/) can certainly help you spend some money and go faster.

The easiest and probably cheapest thing to do would be to off the truck and get one with a 4.0. If you don't have to have a Ranger but still want a truck, find a Dakota with a 5.2 and really haul ass.

http://www.dodgetrucks.org/gallery/data/500/medium/old_school_red_ryder.jpg

posted by  vwhobo

But see I'm 15 and really have a nice first truck so I'm happy with it, I just want to get a little more torque and horsepower because at the wheels its probably only putting down 90-95hp :ohcrap: I'd be satisfied if I got 105hp at the wheels and about 145 lb ft of torque at the wheels.

posted by  99integra

good to see people my age know real world horsepower and torque figures\

but like vwhobo said, increasing stroke would do you worlds of good.

personally id only go for high-revving horsepower in a little car or something,

but since you have a truck, increasing stroke will make the engine feel stronger as long as you keep it below 3500-4500rpm

above that shouldnt feel too much different, but might not be good on your engine. :2cents:

this is just what im pretty sure of, im 15 too and i could be completly wrong:mrgreen:

posted by  nighthawk

Shit yea bro everyone my age I talk to are complete dumbasses thinking NAWZ is the best upgrade since sliced bread

posted by  99integra

...Since when was sliced bread considered an upgrade? :laughing:

posted by  chris_knows

Since the 50's dontcha know :laughing:

posted by  99integra

Wait wait wait, am I missing something here? I remember when you posted the video of you driving your truck on the streets. And you are 15?

posted by  Benson

In Florida (Most of the US) you get your restricted (close to a G2 I think) at 15...lucky bastards :laughing:jp

posted by  chris_knows

If you're only looking for about a 10% gain, think header, cat back, chip and cam. Those combined should get you near 20%. I don't know how much it would cost, but I bet $750 would be close and you could do all the work in one long afternoon.

posted by  vwhobo

I'm too bleary eyed to inch my way through what has been posted, but I am getting the impression there is an advocacy for stroking that will provide better torque. I guess people think that a bigger crank pin (moment arm) results in more engine torque?

Well guys the thing you must design to is BMEP. BMEP is proportional to torque output and maximum usually sits a little under the peak volumetric efficiency. And what things affect BMEP? Well burning fuel over a longer stroke and developing peak cylinder pressure at the wrong time sure as hell isn't going to increase the mean value is it, no Siree Bob.

Given a reference RPM, if you have had experience with cam selection you will know that it's profile will have a marked influence on BMEP. And we all know what a dog an engine becomes at lower revs if you open up an exhaust in isolation, reducing VE and thus BMEP, MBT, etc, etc.

So truth is if you increase your displacement you ideally should burn more fuel, which increases the power. How that power is handled in the form of pressure in the pots, is how much torque can be produced at whatever RPM.

posted by  Wally

Think throttle body too. Stock TBs are stranglers (and for good reason).

posted by  Wally

Whats a throtlle body?

posted by  Aondor

It regulates the amount of air entering the engine (i.e. it throttles the air). The amount of throttling/choking is governed by the amount of travel you put on the accelerator pedal.

If you have a carby engine the throttle plates are generally referred to as chokes. A 2V has two plates and guess what a 4V has.

posted by  Wally

so I xould just move my chokes to get more power?

posted by  Aondor

Max power will be at wide open throttle. If the throttle is too small the VE will tale off and you won't achieve the engine potential.

posted by  Wally

Don't get confused with Wally's use of the English language. When he refers to chokes, that means barrels to us in the US. On the other hand, if you're working on a carbureted engine, removing the choke plates will usually increase airflow very slightly and potentially help top end power. On a street car, keep your chokes for ease of drivability.

Regardless, his thoughts on using a larger throttle body or barrel size on a carburetor will definately give a potential increase to top end power due to increased potential airflow, but it's not a gaurantee based on the rest of the engines components.

posted by  vwhobo

Wally, do you think the stroke on this might produce more torque than his 2.3?

http://www.bath.ac.uk/~ccsshb/12cyl/rta96c_crank.jpg

posted by  vwhobo

Yes I think there is a good case for it having slightly more.:mrgreen:

And yes we call the venturis barrels too, but I was trying to keep the post within strict confines and refer only to the throttle body underneath.

posted by  Wally

What about an underdrive pulley? I have heard some minor issues with these like either raising or lowering a speed of some sort, or is there no issue with these whatsoever?

posted by  99integra

They are supposed to slow down the speed of the alternator, water pump, power steering, aircon compressor, etc. Because these peripherals use engine power, they are often referred to as parasitic and the power used to drive them a parasitic loss to the output of the engine. Slowing there respective speeds means less power use.

Obviously you have to consider the downsides occassioning the changes.

Being a smaller drive pulley, there is less rotating mass, thus less losses.

posted by  Wally

So basically its not the best upgrade or am I missing something?

posted by  99integra

It's used extensively by enthuisists. But remember as you make these changes you move awy from the comfort zones the manufacturer has worked to. There is little point making the mod if you need the power to drive your monster ICE system, if the steering becomes a dog, if the engine overheats, if the air cond doesn't cool.

The call must be made on an individual basis.

posted by  Wally

I don't want to get into anything that deep, I'll just stick with a header, flowmaster 40, 2.5 inch pipes, high flow cat. converter, making the 2.3 to a 2.5 and putting a better radiator and fan in there. Any more suggestions please give me your input, thanks for all the answers so far!

posted by  99integra

I am not familiar with your engine, but I presume there are lots of guys out there that have plug and played for lots of variations to come up with the fastest car that ever was.

When you say headers, you mean what? Are they designed for low end, midrange or top end? Is the 2.5" pipe chosen for any reason? If you are boring and stroking, what are you doing to make sure it breathes appropriately.

Maybe you can provide some specs like valve events and lift, port sizes, valve sizes, stroke, bore, number of valves, compression ratio and I'll do some calcs for you.

posted by  Wally

I'm looking to get a free flowing exhaust like this one http://www.racerwalsh.com/product/RWA1300_R


I chose the 2.5" because that would make it breath better I would think or maybe somethin smaller like a 2.3" so I don't lose that much back pressure.


The bore is 3.780, stroke is 3.126, 2.3Liter, 140 cubic inches, EFI, 9.5:1 compression, 96-105 hp @ 4600, 135 ft/lb@ 2600, that is all I can find really, I need to find my Haynes manual but here are the sites I got this from: http://www.racerwalsh.com/category/techinicalinformation/ ; http://www.wheelspin.net/projectcars/87coupe/87coupe.html I dunno if that will help but thats all I could find right now. :ohcrap:

posted by  99integra

Well I really didn't want to do any leg work and I don't want to be influenced by what others have done. I'll do a little investigation anyway.

posted by  Wally

Torque AT THE WHEELS is king on the street. There are many ways to go about it. Stroking essentially increases piston velocity which isn't any easier on the car than making it rev. If you don't have a big income, stick with the bolt ons and you will have a slight increase across the powerband. I guess what I am trying to say is that torque and revs are one in the same. Don't Chevy guys wish that their flat torque curve went on another 1000 rpm? Wouldn't Honda guys want an extra 20 lb.ft. everywhere?

posted by  VG30DE

2.5 inch is too big of an exaust. Unless you are drastically increasing revs, flow, displacement, forced induction, etc.

posted by  VG30DE

Okay dildo, I'll play your silly games. If you increase torque at the flywheel, after it passes through the rest of the drivetrain, where does it end up? If you answered the wheels, which you should have, then your post was entirely unnecessary. Where exactly did you think I meant the extra torque would be helpful? In the windshield wiper motor?

BTW, how about directing me to the post where I recommended increasing the stroke. Bet you can't find it because I didn't, but... If your head wasn't implanted in your ass, you might be able to see where I did advise bolt-ons.

Oh yeah, final thought so I don't overload your pin head. Torque and revs ARE NOT THE SAME. That is unless you care to explain how engine A produces 200 lb/ft of torque at 1500 rpm but engine B has to spin 5000 rpm to make the same amount. Go back and re-read your Wikipedia a little closer and maybe you'll figure out the answer. Probably not. :banghead:

posted by  vwhobo

hahah...

posted by  CarEXPERT

Hey Welcome back :thumbs:

posted by  chris_knows

lol, I try to make one little point and I get called a dildo. I quoted you for that one line. Sorry I didn't make it clear that I had moved on. Now I remember why I left the forum in the first place. What I meant by torque at the wheels is that you always want a max amount of torque at the wheels to accelerate. Peak engine torque as a number has become fairly unimportant to me lately (as fun as they are to quote from the newest 3/4 ton diesel trucks). What has become important are horsepower and the torque curve, togeather. The more horsepower you have, the more torque you can get to the wheels, and the torque curve tells you how the engine puts it down. Peak engine torque is meaningless because once the torque gets to the ground, it has been multiplied by the gears. And I didn't mean torque and revs were the same literally. I meant that both are necessary to accelerate. If you want a 1000 lb.ft. motor that revs to 1000 rpm, be my guest. I'll race you sometime. My favorite analogy is the American car that revs to 6 with a flat 150 lbft torque curve and 2:1 gears and a Japanese car that revs to 9 with a flat 100 lbft torque curve and 3:1 gears weighing exactly the same with no driver error. Which one is faster?

posted by  VG30DE

I can't think of many american cars with only 150Lb of torque unless were talking about dodge neons

posted by  Aondor

::sigh:: welcome back

posted by  99integra

The numbers themselves aren't that important. Say the American has 300 lbft and the Japanese has 200 lbft. Same thing. The point is the torque rev relationship.

posted by  VG30DE

Pretty much any compact/small/midsize car/truck has had a motor with that or less at some point in the past 10 years. Cav, Neon, Focus (even SVT), Grand Am, Small trucks, Stratus... I am sure I am missing a few.

posted by  VG30DE

No, the reason you got called a dildo is... Because you appear to be one. If you were only trying "to make one little point", then what else was it that you were moving on to? How is one to know that you're moving on when the concept of a paragraph seems to escape you?

Just because peak torque has become unimportant to you, does not mean that it is not a useful tool for those of us who need to know how to gear vehicles to meet specific performance criteria. Additionally, the idea that the more horsepower you have, the more torque you can put to the wheels is simply ludicrous. Very simply torque is work and horsepower is how fast that work is being done. A vehicle with a torque peak of 300 lb/ft WILL ALWAYS be able to put more torque to the wheels than a vehicle with a torque peak of 200 lb/ft assuming equal gearing, no matter how many horsepower each engine produces. Even in many cases where gearing is not equal.

On to your race and analogy. Simply stated they both suck. I'll be happy to take that race as long as your imaginary cars both weigh the same, are geared the same and I get to pick the track And of course your analogy is ridiculous because it doesn't take into account such reasonable factors like as vehicle weight and realistic gearing. Unlike you, I don't live in a world of theory although I do understand it and use it to my advantage when possible. More importantly I have the real world experience to support my statements. I think for now, until I see a reason for it to change, dildo stands.

posted by  vwhobo

Realistically, The jap car with revs would be geared much more aggressively and be about 400 lbs. lighter. You never answered my question. lol. This argument is stupid. I don't really care if you believe me or not. I was trying to "add value" to your statement about torque. Not start flame wars. Revs matter too, period.

posted by  VG30DE

Well, yes I did answer your question, or at least address it, by saying that your analogy is ridiculous. Try reading the entire post.

The argument as you call it isn't stupid, the stupid is emanating entirely from your keyboard. You are the one trying to make this not only American versus Japanese, but also by comparing apples and oranges, making your veiws entirely without merit. You were not trying to add value to my statement about torque, you were trying to change the meaning and at least partially refute it. And no matter how many times you type it, "revs" DO NOT MATTER. It's how the drivetrain is matched to the available powerband.

posted by  vwhobo

Well that depends on your point of view. I guess you impied the more torque the faster the car? Tell that to a Mach truck driver when he gets hosed by a Suzuki one litre at the lights and I think he might have something to say to the contrary.

And shifting the ball out of your court a tad, how can a car's performance travelling in rectilinear motion be measured in terms of torque?

posted by  Wally

I definitely didn't want to make this USA vs. JAP. Now that you officially said revs don't matter, I am satisfied. I definitely read the whole post. I definitely think the analogy is relevant. Without merit? Try reading how horsepower works sometime. Horsepower at the wheels is constant in every gear. Torque is not. Torque curves matter. Do you even understand the analogy? What is your reasoning behind saying that revs don't matter? You are the one without merit.

posted by  VG30DE

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