The un-official car thread of 2010

[mastermg]

I don't care, it's nice as hell haha. As long as it's a coupe.

[Ctrl]

(01-17-2010 04:34 AM)mastermg Wrote:  I don't care, it's nice as hell haha. As long as it's a coupe.

Trust me, you woudn't want one. I've fed gasoline into 3 rotary engined cars over the years and the gas milage is atrocious! So is oil consumption.

[mastermg]

Oh. My dad had an rx7 back in the 80s. He tells me the same thing, that it consumes like a v8. He would never let me think about getting one.
My other friend tells me I shouldn't get a turboed car altogether because the problems that come with it. I think you are best off N/A. I'm kind of stumped.

[Ctrl]

(01-17-2010 09:53 AM)mastermg Wrote:  My other friend tells me I shouldn't get a turboed car altogether because the problems that come with it. I think you are best off N/A. I'm kind of stumped.

This is true. A pound or two too much boost and Mazda's Zoom Zoom Zoom quickly turns into Zoom Zoom BOOM!.

If you build a good engine like I had built, an n/a engine can surpass what a stock turbo model made. A 1988 "turbo II" made about 182hp at the crank. The guy who built my engine at http://rx7specialties.com figured I had about 200hp at the WHEELS.

An n/a wankel will have far more longevity than boosted.

[JohnDoe1984]

You just want an engine built and designed to run high boost. When boost is retrofitted you can never run it very high. 7-12psi. There's people running 40+psi on evo engines. Saab has some cheaper models around that ran a nice high boost engine. People in europe are sticking HX40 diesel truck turbos in em and getting crazy hp.

I would have a hard time going back to N/A. I'm addicted to boost. Turbos are so much fun.

They have so much potential with tuning, different fuels, and the right mods.

Everyone on the turbo forums is raving about corn fuel (e85). I guess it has better knock resistance than race gas + methanol, while costing about 1/4 as much per gallon. You can really crank the boost and timing. It's also safer for the engine than meth injection. If your meth runs out or you have flow issues it will lean out your engine in a hurry and cause a failure. The only big problem is you get reduced fuel economy and you have to run gigantic injectors to get enough fuel. 1000-1600cc depending you your HP goals.

Only some areas have it available. I wish we did.

[mastermg]

Yeah that's the thing, boost is a lot of fun, just less reliable. The Saab aero and Volvo t5 models use pretty high boost stock.
For the 350, turns out something from the tranny shot out, and is no longer connected to the crank. We found a hole and something sticking out of the bell housing. Hopefully, it's just the tranny that needs to be replaced. It's like 300 used on eBay.

[JohnDoe1984]

If you want a good AWD turbo for a good price another car you might look for is an early Subaru WRX.

From what I've read the handling on the stock gen2 DSM's is crap. They need upgraded brakes and suspension to be in the same realm as the evo. A better, more reliable, probably lower cost, alternative to a DSM is a first gen US WRX. The first year was 2001.

Great cars, fairly easy to mod, much better stock than a 2g DSM. I've seen several in good shape going for 5-$10,000.

[mastermg]

I wont bother with 2nd gen DSMs, unless I could find one swapped with a 6 bolt head.


The cause of crankwalk

Why does crankwalk happen, and what causes it to happy almost solely
on 2G DSM's? To answer this question, you need to look at what makes
the blocks different from eachother, and also look at the actual
metalurgy of the 1G and 2G blocks. From our testing, we have found
that the 1G blocks are actually have a more dense iron content than
the 2G blocks, and are actually stronger. If you notice, on the 1993
and up blocks, they almost seem to have a rib-cage built into them
which is on an engineering level, a very good way to increase
structural integrity. However, something happened in 1995 that
caused Mitsubishi to cheap out on the iron content of the blocks they
were casting. Maybe the R&D of the new car got pricey, and they
needed to cut costs in certain areas or what have you, but those
blocks simply aren't made as strong. The next thing you need to look
at is the thrust area, and that main girdle on the 7 bolt blocks.
Again, from an engineering point of view, a good idea for structural
integrity, and it works great on the 93 and 94 blocks, but again, the
density of the 1995 and up blocks just doesn't quite cut it. This
means you can do one of two things. A. completely change the atomic
composition of the block which would ###### cost you more than your
car did, or B. pick up where Mitsubishi left off, and improve upon
their half-assed design. We chose the latter.

Now, know everyone has been concentrating on oiling, and oil
pressure, and the 2G oil squirters suck, etc. however that idea never
quite held water to me. First off, the oil squirter's main function
is to cool the bottom of the pistons. Secondly, under full throttle,
you are getting upwards of 100psi of oil pressure. 15 pounds of
boost is more than enough air pressure to blow off intercooler pipes
if the clamps are less than perfect, so don't you think 100psi of
liquid pressure would be enough to blow out any bits of grease or
grime in the oil squirters? It doesn't look like a lack of oiling in
my book, from what I have seen on a crankwalked motor. The other
thing I've noticed, is in order to find the cause of crankwalk,
people have dis-assembled blocks, heck, even sliced them in half to
get to the root of the problem. What if the root isn't quite that
deep? What if the cause of crankwalk happens AFTER the short block
begins assembly? If you caught that, read on and I'll elaborate.

Another popular theory of crankwalk is that a heavy pressure plate
causes stress on the crankshaft and literally over time and use will
pull it out of alignment. Those people are actually on the right
track, however something else is failing that is allowing the crank
to be pulled by the pressure plate in the first place. Here comes
our idea. Instead of tearing the block down, and looking at oil
passages, or physically examining the thrust surface, we went the
other way and began assembling, and measuring, and seeing what we
would find. We installed the crank and main girdle, and torqued it
down to factory spec. We then bolted a torque plate on the top of
the block to simulate a cylinder head being bolted down, and we
torqued it to factory spec. What we found ater both had been torqued
was compelling. We measured the thrust area before and after, and
found that it would consistently move .0025-.003" when it had torque
on it! Now, for those who have built and blueprinted an engine
before, .0025-.003" may as well be 2 feet in an area that sees as
much stress and has such a critical job as a thrust bearing. To help
illustrate what is happening here, put your hands together palm to
palm. Now, twist your top hand to the right very slightly and your
bottom hand to the right very slightly. When you "torqued" you
hands, notice they tweaked slightly, and are no longer perfectly
straight. That is what is happening to the 2G block when your
cylinder head is bolted down, and your main girdle is bolted down.
You are causing a condition of pre-mature failure, and things such as
heat, and that heavy pressure plate merely aggravate that existing
problem.

So now we have the root 'cause' of crankwalk, but there's more. This
is going to make sense to those people who have assembled a 4G63
before. When you go to bolt down that main girdle, is there any real
way to line it up perfectly straight? I know I know, the bolt holes
line up, the mains kinda sorta lock into place, yada yada...but are
they going on perfectly straight to the THOUSANDTHS of an inch? If
you can eyeball that, then you are a better man than I. I however,
would put a million dollars on it that there is a measurable
disparity between the tolerances of each main cap, and where it bolts
down. Here's a challenge. Cut the head off a main bolt, and tighten
it down in the hole. Then stick a feeler gauge in there and measure
the clearance between the bolt, and the wall of the bolt hole. Did
you catch it? IF it was going on PERFECTLY sraight, there would be
NO clearance, NO disparity. The bolts would go in much like the
dowels on a flywheel..they would have to be hammered in. Ah ha!
Dowel pins.

A few smart(ly) engineered companies have dowel pinned motors from
the factory; such as Toyota and Nissan. There is a reason for this.
If you are relying on 10 bolts to line up your main girdle, is
essence what you are doing is GUESSING that it's going on straight.
Couple that with your block tweaking and throwing the thrust bearing
off .0025-.003" is like shooting yourself in the foot, and not
learning anything from it. The dowel pins come in to line up that
main girdle PERFECTLY, toleranced to the thousandth of an inch, so
you elliviate any guesswork that may be involved. This is why SOME
motors crankwalk, and SOME do not. Some of the girdles just so
happened to be installed better at the factory, and that is
completely by happenstance and good luck. That's it! However, every
single 2G motor out there does indeed have the capacity to crankwalk,
although some people may never experience it at all.

The Fix

Now that we know what is causing crankwalk, we need to look at how to
fix the problem so it doesn't happen again. First things first, you
must start with a completely flat deck to rule out any possibility of
added 'tweaking' due to an uneven surface (obviously if it goes on un-
evenly, some area will have more pressure applied to them, more
stress, than others.) The block is first cleaned and then decked
true. After that, the main bearing journals are align-honed to
insure we are starting with a perfectly machined bearing surface to
begin with. Then the block needs to be flipped over, and
the 'bottom' end is drilled and machined for dowel pins at 5 points
on the bottom of the block. Matching points are drilled and machined
on the main girdle (obviously, SERIOUSLY close measurements are taken
to ensure everything is perfect..no close, PERFECT.) Just about the
only thing that will withstand than kind of heat is billet steel.
Dowels are formed out of billet steel, and installed into the block.

Obviously at this point, the crank has been inspected, all neccessary
machine work is performed, and it's ready to be installed into the
motor with new main bearings, and new main bolts. The girdle is then
installed on the dowel pins, and hammered down into place. The
dowels are so tight, and fit so well, that you can easily life the
block by it's girdle without any bolts in it. Then the new main
bolts are installed, and torqued to factory spec. The block is
flipped over, and a torque plate is installed to simulate the
cylinder head being bolted down, and then torqued to factory head
bolt specs. The thrust area is measured with everything torqued,
tolerance disparity is recorded, and the block is disassembled. The
crank and bearings are removed, and the process or torqing the torque
plate and main girdle is repeated minus the crank and bearings, and
then the thrust area is re-machined with everything torqued down to
be 100% perfect again. Not close, perfect. The bearings, crank, etc
are all re-installed, and re-measured. The thrust bearing now did
NOT move. Dowel-pinning the main girdle ensured that it went on
perfectly straight every single time which eliminates guesswork and
allows for precise machining.

Regards,

[JohnDoe1984]

When they refer to those 4g63's as 6 bolt and 7 bolt. That number applies to the number of bolts that the flywheel bolts the crankshaft with not the head.

If you want a six bolt you need a six bolt block not a six bolt head. If you're scared of 2g you can always go 1g. It's more in your price range anyway. Some careful searching can yield you a 1g in good shape. There's a few still looking good driving around even up here in Alaska.

[mastermg]

Oh I didn't know that haha. Thanks for the help.

[yeti]

(01-10-2010 07:11 AM)Ctrl Wrote:  I wish there were more car buffs to speak up here...I know the "truthers" tend to be dominated by a lot of "vegan-greenies" but surely the rest of you don't bike to work?

I just don't like to talk about the fact that i paid $35,000 for a WRX and sold it for $19,500 4 years later... to pay off a $25,000 debt...

I was making $120,000 when i bought it, and $0 when i sold it. I should have moved into my car and driven it to somewhere where i could live in it instead of paying 4 more months of rent in a shithole...

Having said that, i'll never get a car loan again.

[JohnDoe1984]

I would more say that you shouldn't have paid $35,000 for it in the first place. Careful shopping in the used market could have landed you a lightly used one for $15-20. I know, I'm speaking to the choir. I don't like having someone else's beat up problems either. I did buy a new car once. It's not that hard when you do have the money.

I would have never bought the evo new though. If I didn't fall into a steal of a deal I wouldn't own one. I have the original sticker it was over $35,000 as well.

So, other than the fact that you had to get rid of it the WRX was a great car though?

Subaru's in general are like the honda civic of Alaska. There's more of them on the road than anything else up here.

[mastermg]

That really sucks Yeti. Atleast you had fun with it while it lasted, right?

[mastermg]

Time to bump this up from the dead!
For an update, my friend sold the prelude and got a BMW 540i, 4.4 liter v8 6 speed manual car. It's running over 300 hp with a Dinan cold air intake, Dinan air intake manifold, and a Dinan exhaust.
As for me, I sold my Integra, and am looking at the 2nd generation Toyota MR2 turbos. For a car as old as me, these cars are pricey! However I like the Ferrari look to them, and the rear engine pushing 200 hp stock. I'll update if I buy it.

[Nokturnal]

Damn didn't realize there were so many gearheads in here haha.

I've been saving up my money and considering what to get. I looked at the Integra for a while but figured it would cost me too much to mod it in any meaningful way. Right now I'm pretty set on a S13, those things are sexy and can run a bit of turbo without any engine mods.