Dave, is this 100 mm stroke crank even as strong as the 1G 6 bolt crank from factory? Concerned about the 2G ' crankwalk' thing..

 

Toda does not recommend that you exceed 500hp with this kit (They did not specify BHP or WHP). They claim the the rods are the limiting factor. They also do not recommend that you exceed 7500 rpms. Wait for Dave to make some modifications to the kit before purchasing IMO. I purchased the Toda kit and wound up replacing the rods and the crank.

 

What about the kit that Magnus sells? If the rod is an aftermarket rod then its ok right I suppose. Hey do you all know that Mitsubishi has a diesel block, 7 bolt, its called the 4D68T with a 93 mm stroke which will give you a capacity of 2.2 litre. 1 mm short of the Jun and Tomei cranks..

 

Any plans to put together a JUN stroker? hmm, hmm?

 

So David,

Are you having a change of heart concerning what is going on with stroker technology/quality these days, or are you simply providing what customers are asking for?

 

Did you guys see the new Crower kit coming out? Looks to be very impressive but possibly expensive...

 

Got a link Jack?

 

Because for many of you, your EVO is also your daily driver here is how I would figure out what motor best suits your needs decide what you want the car to be capable of and how much $ you want to end up dropping on it then: the factory heads were designed for a maximum "optimal" airflow @ 6500 rpm (the factory cam profile & valve lift are calculated from the CFM of the head) to make "real" power gains beyond this you can run lots of extra boost or port the head. True changing the cam w/out porting the head can help, but scince there isn't a big change in airflow w/ higher valve lift on the stock head changing the cam profile isn't going to get you as far as you may think. Once the head is ported & flowed you can calculate @ what RPM you will make max optimum airflow also the VE of the head 1st theoretical CFM= (RPM x Eng Displacement in inches)/3456 then VE= (actual CFM/Theoretical CFM)x100. Once you figure out @ what RPM the head is going to work the best @ then use this formula: (4000fpm x 6)/your redline =optimal "safe" stroke. Assuming you don't have an unlimited budget for custom parts now would be the time to pick an existing crank that is as close as possible to your optimal stroke. As for picking rods and piston height keep in mind longer rods can safely rev higher they cause less wear between piston & cyl wall & more dwell time @ TDC=higher VE. On the other hand longer rods decrease low end torque but they increase top end HP Its usually better to stick w/ something in between so you don't have to worry about extra machine work due to clearance issues.
Now if doing head work goes above & beyond what you want to do and you want to build a "stroker" motor keep in mind the stock head capabilities & piston speed (4036 fpm @7k) if mitsu like many other car companies uses 4000 fpm why should we change it.
Bore x Bore x stroke in inches x .7854 x # of cyl = CID= basic algebra, for example change CID from 122ci (2.0L) to 142 ci (2.32L) 142 / 4 = 35.5, 35.5/.7854= 45.19, 45.19/ 3.46=13.06 the square root of 13.06 is 3.61 thats an over bore of .2600" while maintaining the stock stroke, now thats alot of machine work & some of you might be saying that leaves the cyl wall too thin so just insert different #'s into the equation at least now you have it if you didn't already. There are many companies to choose from for pistons & rods just because they don't show a particular size on their application list doesn't mean you can't get them to make it for not much difference in price. Shop for pistons that have the closest to stock piston to wall clearance in the end you will end up w/ less wear and if built right longer lasting and more reliable than an off the shelf stroker kit
(the math is all fact the ideas on how to come up with your own motor are soley based on opinion, experiences, and uncountable hours of traning from a couple of guys who have been building engines longer than most people on this forum have been alive (myself included))

 

Vivid,

Using a 100mm stroke, stock length EVO rods and bore size will stay as small as possible in the stroker kits I am doing to keep the block as rigid as possible. The cylinder head will be up to the customer. Of course I am going to recommend if you are going to stroke it you may as well port the cylinder head.

Zeus,

Not having a change of heart on the stroker engines yet. I am just getting with the program. Just like the ball bearing turbos. If the market says build it I am going to do it, it is business. I am NOT going to build a piece of crap though that doesn't work just to make money. The strokers that I ran in the past all failed in one way or another. Looking back on many of the things we did...........we shouldn't have. Talking with the machine shop and pistons and rod manufacturers about it all now the new parts we are having built may just work out really well. For now there are guys making good HP/torque numbers with the varisous kits out there, Today, Jun etc. I didn't see any reason to NOT put together one of these kits (Toda in my case) and offer it. I had the block and our machine work is top notch. I figure if someone wants it atleast this is as good as the kit can get, may as well buy it already assembled from us.
I am hoping for great things from the new kits we are putting together. Time will tell. It will be hard to get me to switch from the 2.0, we have made so much reliable power with it that changing to something else is hard to do.

David Buschur
www.buschurracing.com

 

Great response I'm sure it will work out well for the daily driver/weekend warrior. I'm curious to see if it can reliably do what you have done with the 2 liter.

Last question from me on this subject. MalibuJack, myself, and others are curious as to how the OE, or better yet, the OE 10.5T turbo would run on the larger displacement. I'm sure it would suffer at race gas boost levels, but what about street level pump gas performance? Would the slight bump in displacement really take the breath out of the top end of such a set up?

 

My personal opinion is the extra displacement moves a bit more air.. and has a bit more exhaust, so you should experience earlier spool, however the stock and 10.5t turbos might run out of breath a little earlier *IF* you don't make efforts to remove restrictions to offset the amount of additional work the turbo would do.

I chose the 10.5t hot side specifically because I planned to run slightly more displacement, however I do plan on using a ported head, intake manifold, throttle body, and I already have the blowthrough MAF... the less work you make the turbo do, the less problems you will have.

Now with that said.. the stock turbo (and the Ti one also) will certainly run out of breath at higher RPM, but I don't think it'll be as bad as would be expected... Definitely not bad on pump gas for a street vehicle..

My personal opinion is that I'm not overly interested in the track, and I dont think a late peaky HP/Torque curve is very useful for street driving, I don't find the need to dangle my dyno sheets for all to see... I just want to get some decent times on the track for the few times I plan on attending. But I'm a street guy (and like the twisties too).. always have been, always will be..

 

Then FWIW you would be paying in essence a $1000 if you have to give your shortblock back.

 

Of course the key is cost.. But we are talking about David Buschur here, so the new kits should certainly be cost effective..

I'd much rather have the machine work and assembly done locally (simply because the cost of shipping the core, then shipping back, plus the assembly)

FWIW the short block weighs just under 170 pounds.. pretty damn light for all that power..

 

...and my opinion is basically the same. I just wanted an opinion from David as to how much of a differece the increased displacement will cause boost/power to drop off the top end at pump gas boost levels. I'm a street guy myself, but want a good look at the "big picture" also.

 

I'm sure we'll hear something soon..