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Dispelling Myths about the G54B Bottom End!!!


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Ok guys, the information I gathered in this post was from an attempt to understand how to make the G54B engine produce torque in the upper rpm range and thus produce horsepower - a high horsepower engine is one that produces torque in the upper rpm range.

 

I've read lots of posts suggesting that the G54B cannot produce high hp because of an unfavorable, bore, stroke and rod length. I've also seen attempts and suggestions to de-stroke the engine to increase hp etc...

 

So I decided to find out more about, Bore/Rod Rations, Rod Ratios and Rod Angles and compare the G54B to other engines.

 

I also decided to research and learn from the Ford 2.3 engine that has very similar characteristics to the G54B and has been proven to produce insane levels of hp. There is lots of data available for this engine and extensive after-market performance parts from which we can learn.

 

Here are some theoritical benchmark figures to keep in mind when looking at the numbers. These figures theoretically produce a high reving, high hp engine. Also keep in mind that these figures were develop based on the V8 engines and might be skewed for our application, but still serve as a guideline.

 

1.75 < Rod Ratio < 2.1

Rod Angle < 17 degrees

1 < Bore/Stroke

 

So here are the numbers:

 

Mitsubishi G54B - Starion

-----------------------------

Bore: 3.5875"

Stroke: 3.858"

Rod Length: 6.570"

Bore/Stroke Ratio: 0.93

Rod Ratio: 1.70

Rod Angle: 17.07

Intake Valve Size: 1.8"

Exhaust Valve Size: 1.5"

Intake and Exhaust Valve CFM on Ported Marnal Head @ 28"

.400 211 141

.500 223 155

.600 229 160

 

Ford 2.3 - Mustang SVO

----------------------------

Bore: 3.780"

Stroke: 3.126"

Rod Length: 5.20"

Bore/Stroke Ratio: 1.21

Rod Ratio: 1.66

Rod Angle: 17.49

Intake Valve Size: 1.74"

Exhaust Valve Size: 1.50"

Intake & Exhaust Valve CFM on Stock Ported Head @

.400 202 156

Intake & Exhaust Valve CFM on Esslinger Aluminum Head @ 28"

.400 201 154

.500 228 172

.600 241 183

 

Mitsubishi 4G63 - Eclipse

----------------------------

Bore: 3.366

Stroke: 3.465

Rod Length: 5.906"

Bore/Stroke Ratio: 0.97

Rod Ratio: 1.70

Rod Angle: 17.05

 

Mitsubishi 4G64 - Galant

----------------------------

Bore: 3.41"

Stroke: 3.937"

Rod Length: 5.906"

Bore/Stroke Ratio: 0.87

Rod Ratio: 1.49

Rod Angle: 19.48

 

Nissan VG30DETT - 300zx

------------------------------

Bore: 3.445"

Stroke: 3.270"

Rod Length: 6.071"

Bore/Stroke Ratio: 1.05

Rod Ratio: 1.86

Rod Angle: 15.62

 

Nissan SR20DET - Silvia

----------------------------

Bore: 3.386"

Stroke: 3.386"

Rod Length: 5.366"

Bore/Stroke Ratio: 1.00

Rod Ratio: 1.58

Rod Angle: 18.39

 

Nissan RB26DET - Skyline

------------------------------

Bore: 3.405

Stroke: 3.386

Rod Length: 4.780

Bore/Stroke Ratio: 1.01

Rod Ratio: 1.41

Rod Angle: 20.74

 

Toyota 2JZGTE - Supra

---------------------------

Bore: 3.405

Stroke: 3.386

Rod Length: 5.59

Bore/Stroke Ratio: 1.01

Rod Ratio: 1.65

Rod Angle: 17.63

 

 

Now, if you didn't notice, here are a couple of interesting things to point out:

 

The most striking comparison in my opinion is how similar the G54B is to the 4G63!!!! All three factors are pretty much equal!!!

 

The next interesting thing is how the bore/stroke ratio on the Nissan and Toyota engines, the legendary powerhouses, are all pretty much equal to 1.

 

Finally, I take special interest in the Ford 2.3 engine comparison to the G54B since they are so mecanically similar.

The G54B has a slightly better Rod Ratio and Rod Angle, while the Ford 2.3 has a slightly better bore/stroke ratio, which probably put both engines at the same vantage point.

Both engines also have about the same size intake and exhaust valves and are both SOHC.

 

So if the G54B engine is so similar to the Ford 2.3, why are so many more 2.3 Fords producing in excess of 400hp and some even close to 600hp, propelling cars to 11s and 12s 1/4 miles?

 

I believe that the answer lies in our heads. The Ford 2.3 aftermarket, more specifically Esslinger, offers performance iron and aluminum heads for the engine that outflow even a fully ported Marnal head. These heads also take bigger valves and come with a variety of proven after-market performance cams.

 

So, in conclusion, guys, leave the 2.6 bottom end alone and lets focus on developing our heads and as Esslinger puts it himself: "The most substantial gains in horsepower will be made by modifying your current cylinder head or better yet, replacing it with an Esslinger Aluminum head." (kind of a sales pitch, but you see the point).

 

wasabii.

 

 

Resources:

-------------

http://www.merkurencyclopedia.com/

http://www.turboford.net/

http://victorylibrary.com/mopar/rod-tech-c.htm

http://www.starquestclub.com/

http://t-racing.com/Tech_Pages/cylinder_head_tech_page.htm

http://www.esslingeracing.com/faq.htm#

http://www.starquestclub.com/forums/viewto...ting+rod+length

http://www.coximport.com/jepistons/apps.html

http://www.wallaceracing.com/enginetheory.htm

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A long stroke limits RPM becasue of higher pistons speeds and piston acceleration, the 2.6 has a very long stroke (.732" longer thatn the 2.3 Ford).

 

A smaller bore limits valve size.

 

So for similar sized motors a shorter stroke, larger bore motor has more potential. That does not say we are anywhere near that and or improvments cant be made. Just to note differances.

 

Kevin C

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Good resesarch! You seem to have come to the same conclusion that many of us have (albeit less scientifically), that breathing is the real trouble spot for our engine. And the only really practical improvement is to port the crap out of the head, and better intake and and exhaust manifolds.
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A long stroke limits RPM becasue of higher pistons speeds and piston acceleration, the 2.6 has a very long stroke (.732" longer thatn the 2.3 Ford).

 

A smaller bore limits valve size.

 

So for similar sized motors a shorter stroke, larger bore motor has more potential. That does not say we are anywhere near that and or improvments cant be made. Just to note differances.

 

Kevin C

 

Very true and that explains the Ford bore/stroke advantage, but interestingly enough, both the Ford 2.3 and Toyota 22R engines use stroker kits to increase their performance!!! Esslinger for example offers a stroker crank with a stroke of ... 3.850"... seems familiar :). Because of the Ford's bigger bore though, this stroke increases displacement to 3.0L.

 

As far as our heads go, I think that the Magna heads might give us the edge we need with the possibility of inserting some 50mm valves (1.99") and the extra porting capability.

 

I just can't wait for someone to come forth and actually confirm the flow numbers that we've been hearing about: 285CFM!!!

 

 

Good resesarch! You seem to have come to the same conclusion that many of us have (albeit less scientifically), that breathing is the real trouble spot for our engine. And the only really practical improvement is to port the crap out of the head, and better intake and and exhaust manifolds.

 

That's exactly the point of my post :wink: getting the facts and numbers down and enough with the "I feel" or "I think" kind of theories :lol:

 

Happy that you guys appreciate it, I for a fact feel much better about the G54B and more focused on what needs to be done.

 

Later.

 

wasabii

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As always and Im surprised no one has beat me to it. The majority of our G54's are untuned. You can make them rev if you do it right. Just refer to Artinists Dyno sheet in the 300whp club. I think people are just too afraid to run the larger turbo's need to move our cars.

 

phil

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A long stroke limits RPM becasue of higher pistons speeds and piston acceleration, the 2.6 has a very long stroke (.732" longer thatn the 2.3 Ford).

 

A smaller bore limits valve size.

 

So for similar sized motors a shorter stroke, larger bore motor has more potential. That does not say we are anywhere near that and or improvments cant be made. Just to note differances.

 

Kevin C

 

Very true and that explains the Ford bore/stroke advantage, but interestingly enough, both the Ford 2.3 and Toyota 22R engines use stroker kits to increase their performance!!! Esslinger for example offers a stroker crank with a stroke of ... 3.850"... seems familiar :). Because of the Ford's bigger bore though, this stroke increases displacement to 3.0L.

 

As far as our heads go, I think that the Magna heads might give us the edge we need with the possibility of inserting some 50mm valves (1.99") and the extra porting capability.

 

I just can't wait for someone to come forth and actually confirm the flow numbers that we've been hearing about: 285CFM!!!

 

 

Good resesarch! You seem to have come to the same conclusion that many of us have (albeit less scientifically), that breathing is the real trouble spot for our engine. And the only really practical improvement is to port the crap out of the head, and better intake and and exhaust manifolds.

 

That's exactly the point of my post :wink: getting the facts and numbers down and enough with the "I feel" or "I think" kind of theories :lol:

 

Happy that you guys appreciate it, I for a fact feel much better about the G54B and more focused on what needs to be done.

 

Later.

 

wasabii

 

You can get a stroker crank for a 2.6 and bring it up to about 3.0. I have built a few stroker motors (sm block chev, sm block dodge) with good results.

 

What would a 90 mm stroke get you compared to 98 mm? Well if piston velocity is the limiting factor you should be able to rev an extra 500 rpm with the same ROD & Piston loading (calculated at 8000 RPM). The effective displacment is now slightly lower (RPM X displacment) at the same inertia loading.

 

Any advantages? You get more firings per second, Might help if you are octane limited or torque limited.

 

Would this be an advantage? Possibly... But there are lots of factors.

 

I agree with the basic point... Most power is in the top end of the motor. There is always something to be said for a well built shortblock, there is HP there as well. But again as you said its mostly in the top end (head valves cam etc) where you will find good gains.

 

 

Kevin

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what would you do about the timing cover and timing chain length ?
the g54b block didn't start out as a 2.6, there was a previous 2.0 version from the 70s and I heard of possibly a 1.8

 

the guy with the destroked 2.6 using the 2.0 crank with the toyota pistons, did you see that one?

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Guys,

 

I saw an interview with Gale Banks awhile back and he said,

You can add all kinds of modifications to an engine, change headers, intakes, more fuel, but if you don't modify or change the head, you want see much HP.

 

wasbii, I agree. The only thing really holding these engines back are the heads.

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We could use a 4V head.

 

I witnessed on my own setups just how much porting, a header and running a larger turbine housing improved flow, I mean noticably.

 

I keep saying it, if we had a 4V head we would be right up on the 4G63... that IS the key advantage... the 4V head.

 

A stock DSM 4V head flows more than my aggressive race port 2V head.

 

Your going to use that additional flow, always...

 

That's why I think people are *totally* retarded when they say porting does not help at all on turbo...Corky Friggin Bell or not, he ain't got a 4G54... ;)

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Exactly....

 

A more accurate statement is you can get a lot of gains from just a turbo without the need to port.

 

When you dont have a turbo , porting is one of the essential tools to get better breathing. When you have a turbo you can get more air flow by turning up the boost ( to a point).

 

At some point you just cant ignore the head. 5% more flow is 5% more power, turbo or not.

 

Years ago Circle track magazine did an article on racing normally asperated 2.6 mits engines and 2.3 ford engines in econo circle track classes. Both are used and a pro builder did a writeup of each engines strenghts and weaknesses (the article was in 1985 or so).

 

Lots of good flow data, I wish I still had the article and wonder if its possible to get such a old back issue.

 

Anyway, the bottom line on the 2.6 head was the head porters conclusion was a good gain in flow could be had by raising the exhaust port to reduce how sharp the short side radius was.

 

The floor of the port and the roof were modified by tig welding, it was quite the porting job and the improvments were pretty good (from what I remember).

 

Anyone have any ideas on how to find a 20 year old magazine article?

 

Also there are a few gains to be had in the bottom end. None one mod is a huge improvment it's more a of sum of small things.

 

If you are going all out:

 

1: Go for a minimum overbore and use a deckplate when you hone. This gets you reduced friction and better sealing

 

2: Open up the block by removing the extra wings the enclose cylinder #3. That promotes better breathing in the block.

 

3: If you have forged pistons choose a set that has a thin top ring made of steel. This reduces ring friction and on a long strok motor you have more friction. This is the standard ring that come with .035" over pistons, it would be nice if that rings was availible at .020 over but its not.

 

4: Run a wider second ring gap. This insures a proper pressure differential across the top ring so it seals. This is a standard practice on GM and Ford engines.

 

5: Floating pins reduce friction. If you have forged pistons there is no reason not to float the rods.

 

6: The oil pump is a drag. If you dont have ballance shafts its possible to run larger pump at engine speed reducing drag. Extra oil pressure wastes power and once the ballance shafts are gone you have more volum than you need. The upside of extra pressure is you get more volume from the oil squirter to cool the pistons. The down side is that you have more oil to whip around the crank.

 

7: Some type of windage tray helps. We have a long stroke crank thats close to the oil. If there is room, a deeper oil pan helps to get the oil away from the crank.

 

http://members.cox.net/kevincar1/oilpan.jpg

 

I made a spacer out of aluminim tooling plate for my truck pan and deepened the pickup the same amount. Yes thats a spare pan and it needs some cleaning!

 

Kevin C

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2: Open up the block by removing the extra wings the enclose cylinder #3. That promotes better breathing in the block.

 

 

Kevin C

 

 

 

Kevin, you mention the extra wings on the block... here's what I have done to mine... it does breath better than the last setup... I did not go into the other wing side because I didn't want to possibly comprise the block strength somehow.

 

My opinion is this should be a mod done to every block if it is apart, these things need to breath better...

 

As usual Kevin...awesome info....

 

 

 

http://a6.cpimg.com/image/80/35/19619456-6e64-02000180-.jpg

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http://www.geocities.com/spun_bearing/

 

Not the best pictures, but you can see some of the wings.

 

http://members.cox.net/kevincar1/blockwings.jpg

 

The wings pointed to by the red arrows.

 

The green arrows point to sections that are not as closed in around the crank. The idea is to make the areas with the red arrows look like the ones with the green arrows.

 

I had a block in the mill last night adding oil jets and removing extra material.

 

BTW... Mike nice looking engine!!!

 

Kevin

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keeping the torque up is the challenge

 

Other than the fast hard core g54 enthusiasts moving on, a major part of why g54 are still where they are, is NO testing done whatsoever.

Perfect example; something as fundamental as a camshaft dyno/ET comparison vs stock, you will find everywhere else, but not in starquest land.

 

Specs alone mean nothing more than what a cam 'should do'.

Look at all the controversial DSM cam threads, and how many years it took just to come up with an "equal" to the HKS benchmark. You'd think to copy a proven bumpstick (the HKS) was simple enough, eh.... let alone come up with a new grind that actually works. Guess again

 

To add, I've experienced first hand what a *huge* difference a "correctly designed" camshaft can do for a 2 valve motor.

 

I never saw any reason to alter the g54 stroke

 

If you prefer its tq delivery or you get off on 'headflow' and 'hp numbers' like most, go 4g63.... BUT.... if actual street performance is your priority, the g54 tq has proven to hold its ground solid.

example;

One 2.6 went 12.4 at a mere 13psi on a "small responsive turbo".

Another street g54 gone 11.3 on stock 2.6 cam.

 

Seen any 4g63s (same weight) match that ?

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keeping the torque up is the challenge

 

a major part of why g54 are still where they are, is NO testing done whatsoever.

 

That explaines putting 1.6 ratio roller rockers on a stock cam.

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the idea that the stroke of this engine is someone hindering it any way is as an idea that belongs in the 80s just like those who think backpressure is a good idea on a turbo car.

 

my car made over 300hp at 7000rpm and on my next tune i bet it will make 350. our heads flow plenty enough.

 

there is only one and only one reason that other engines make more power than ours. its becasue they came MPI originally and a lot more research, testing and money went into them vs. what we experiment with in our own garages every once in a while, or else our engine hardware is just as good if not better than their "powerhouses"

 

if there were 5000 shops modding G54 instead of the G63, I bet it would leave that engine in the dust even with it extra 8 valves.

 

you can have all the valves in the world but if the engine isn't singing to a good tune, it won't be worth listening to.

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the idea that the stroke of this engine is someone hindering it any way is as an idea that belongs in the 80s just like those who think backpressure is a good idea on a turbo car.

 

my car made over 300hp at 7000rpm and on my next tune i bet it will make 350. our heads flow plenty enough.

 

there is only one and only one reason that other engines make more power than ours. its becasue they came MPI originally and a lot more research, testing and money went into them vs. what we experiment with in our own garages every once in a while, or else our engine hardware is just as good if not better than their "powerhouses"

 

if there were 5000 shops modding G54 instead of the G63, I bet it would leave that engine in the dust even with it extra 8 valves.

 

you can have all the valves in the world but if the engine isn't singing to a good tune, it won't be worth listening to.

 

 

 

I agree with you 100% , I think after 24 months of working on my own car I will be that shop that will leap forward on G54B hp !!!! With the one I own now it makes 15 starquest for me , I know that sounds a bit insane but I'm not proud to say that its true . Soon you'll know just what I mean by that ......But I must say that you stand with just a few on that statement .

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the idea that the stroke of this engine is someone hindering it any way is as an idea that belongs in the 80s just like those who think backpressure is a good idea on a turbo car.

 

my car made over 300hp at 7000rpm and on my next tune i bet it will make 350. our heads flow plenty enough.

 

there is only one and only one reason that other engines make more power than ours. its becasue they came MPI originally and a lot more research, testing and money went into them vs. what we experiment with in our own garages every once in a while, or else our engine hardware is just as good if not better than their "powerhouses"

 

if there were 5000 shops modding G54 instead of the G63, I bet it would leave that engine in the dust even with it extra 8 valves.

 

 

 

you can have all the valves in the world but if the engine isn't singing to a good tune, it won't be worth listening to.

 

 

 

amen

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the idea that the stroke of this engine is someone hindering it any way is as an idea that belongs in the 80s just like those who think backpressure is a good idea on a turbo car.

 

my car made over 300hp at 7000rpm and on my next tune i bet it will make 350. our heads flow plenty enough.

 

there is only one and only one reason that other engines make more power than ours. its becasue they came MPI originally and a lot more research, testing and money went into them vs. what we experiment with in our own garages every once in a while, or else our engine hardware is just as good if not better than their "powerhouses"

 

if there were 5000 shops modding G54 instead of the G63, I bet it would leave that engine in the dust even with it extra 8 valves.

 

 

 

you can have all the valves in the world but if the engine isn't singing to a good tune, it won't be worth listening to.

 

 

 

amen

 

It's simple...

 

The displacment of this motor is based on a longer stroke, that longer stroke/ smaller bore limits valve size and the maximum RPM.

 

The question is would it help to reduce the stroke? IMHO no...

 

What would be better? A larger bore and head to match.

 

The big picture? The maximum HP you can make per CI may be lower but its a larger motor than most fours so its less of an issue. You would care if you were racing in a class that had a CI per pound factor.

 

For the street, bigger is better.

 

It is correct that most of a motors potential is in its breathing. And the factory left us plenty of room to improve. For its time the turbo system was good, that was a long time ago.

 

The intercooler pipes are small, the exhaust very restrictive are the two biggest weak points... and The EFI is limiting.

 

The good points of the 2.6? Very strong block, strong rods, strong crank, OK cyl head. You dont need to do a whole lot to keep this motor in one piece.

 

No block supports are needed , closed deck, lots of iron.

 

What would a 4 valve head get us? About a 15% increase in valve area and better port geometry. So the flow increase would be signifigant. The upside is the motor is 30% larger than most fours.

 

 

As an example:

 

However if a four vavle 2.0 can turn 9000 rpm (vs 7000 for a 2.6) and has a four valve head its going to be able to make more peak power (15%+ or more).

 

The upside is with a lower RPM motor you dont need as much cam, so its likely to be more streetable and have HP and TQ thats very easy to use.

 

Kevin C

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