The spacing between 4th and 5th on the 5 speed EVO tranny is huge compared to the spacing on the rest of the gears. If you look at the actual "speed at xxx RPM" chart for the MR 6 speed and the GSR 5 speed you will see that virtually all the gears match up all the way up to 4th gear. Then the MR 6th gear is almost a direct match for the GSR 5th gear with the MR's 5th gear filling in that huge gap that the GSR has between 4th and 5th.

I hope I explained that well enough to understand

Keith

 

The 5th gear in an EVO is just too tall and the shift alone kills your time. Got to keep it in 4th.

 

Thanks JJ and Fourdoor, it is clear. It is so good that this new point could surface - given the lack of circular argument to drown it out.

I find it amazing that the NDRA / NHRA Pro classes would not have a custom gearing option, or that they even run stock transmissions? Surely they are not running H gate stockish trannys and running mid 7s? If anyone can clarify what trannys they run, I would be most grateful.

Best regards

 

I am a DSM Guy and have worked on a couple blocks. Buschur being my greatest source of info and parts for my buildups. If you search his site or even talk to him he will tout the power potential of a 2.0 VS. a stroker. Above all he states the reliability of the 2.0 and its power production potential and its reving capabilities. For these reasons the motor makes higher power levels more reliably. Al Friedman from Dynoflash along with TurboTrixx states the same and run the same 2.0 displacement in terms of reliability and drag racing. Buschur also denounces the reliability of the stroker in making big power but then again he advertises and sells a stroker kit too so it is hard to judge advice form a vender.



I think it was Shaun who stated

Quote:

Are the stroker drag 4G63s slower because the engine is, counter to physics, inherently less powerful?

and I believe this to be so because you are limiting it’s power band by 2000 RPM’s or so. Many tuners are in business for themselves such as Buschur and their success, no matter the formula, is their claim to dominance in tuning and engine building. I believe that they are in search of the most power and fastest times and I believe that they would use the best means possible, they all seem to choose a high reving 2.0 block, a GIANT turbo, and some Nitrous to get it spooled at the launch. All these tuners state the benefits of reving and I think you must in order to get the big power.





I myself prefer a stroker and have seen what a 2.3 can do on the street, unfortunately I never have the funds to do it properly so I stuck with my stock 1G bottom end which is fairly stout to being with and just put in some 2G pistons which is more then strong enough to handle the 20G. I am not too well versed with the potential of strokers but from what I hear on the drag racing scene is that it is a negative attitude.

 

JJ and Fourdoor made an excellent point about the need to hold power to higher RPM given the lack of custom gearing options.

I think there first needs to be confirmation that the top teams are indeed gear limited - gear limited in terms of not having the option to gear the car right for the powerband of a 2.4. I can see some privateers running 9s and 10s being reluctant to convert to a pure race transmission, but I find it difficult to believe that the pro NDRA or NHRA guys running mid 7s would not have gearing options or that they even use a remotely stock tranny.

If, and once there is positive confirmation that they are indeed gear limited , then we can proceed to discuss the questions raised in post 87 ( https://www.evolutionm.net/forums/sh...5&postcount=87 ) . If it can be proven beyond a reasonable doubt that it is not due to those forces influencing the technical benefits of a stroker, then we can proceed to try and figure out the weaknesses in them. So far on this thread, there has been no reasonable point made against strokers except for the lack of gearing options for the stock transmission. Better yet is if someone gives us a clear and logical reason for the alleged weakness. That way we don't even have to spend too much time or effort find the weakness ourselves.

Finally, power is not purely dependent on RPM. Power is dependent on volumetric flow (density constant). Volumetric flow is dependent on valve area in combination with large displacement, or in combination with RPM. Valve area is fixed by the head. Secondary to valve area is flow efficiency. So given fixed valve area and port efficiency, there are two approaches to power - RPM or displacement. The stroker takes the displacement approach.

 

Take a look at this Shockwave file for a graphical explanation.

http://www.evoclub.net/history/evo8/swf/power_train.swf

Anyone who has spent any amount of time driving a stock Evo 7 will tell you how the car just dies after 4th cos the gearing is just too tall.

 

This is actually a good question. Send Dave Buschur a PM, I had a bunch of his quoted regarding his findings on strokers and that they are not as reliable and not making as much power. He advertises that the 2.0 is FAR more reliable at these WHP levels. But you are correct in the sponsorship cash flowing to advertising parts, it’s the name of the game. But then again Buschur advertises Buschur. Ask Al Friedman and ask TurboTrixx and they will say the same on the benefits of a 2.0.

By far the worst stroker kit using 4G64 rods I believe IMHO. It may be fairly inexpensive though/ The 2.3 is limited to 8500 RPMS as advertised by AMS.

IMHO if you wana stroker, go JUN, 2.2 and 9000 RPM’s and I believe there is an Evo making over 700WHP with it. It is a proven kit for sure and is very expensive and I think more rare for sure.

 

thanks for all the info guyz....specially shaun who put time and effort to share his knowledge in displacements....keep em coming tho.....this thread is not yet finished....
there is more discuss.

also i am looking into the jun 2.2 liter kit.....expensive yes!!!!!

 

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I am researching building a motor for my MR. I agree with the torque benefits of a 2.3L; but is the rpm capability of a 2.0L better suited for the shorter 6spd (I plan on running GT30 or GT35 turbo)? Even with a Vishnu stage 1, it seems like I'm always into the rev limiter. Thanks

 

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Dave Burschur said stroker kits in the past have been designed with errors and that these errors have been corrected and he's waiting to see how they perform. Dynoflash Al says 2.0 is his personal preference. So let's not put our words into their mouths.

Like I said, I don't want to get into this tuner said YYYY, and that tuner said BBBB, unless the points by themselves carry weight. A discussion involving many little unexplained blurbs is quite worthless IMO. Everyone is better off using their own minds and discussing calculations, concepts, obervations, logic.

Post 87 and 95 in this thread have not been addressed.

=============

Electric Evo.. you're welcome.

 

Try this....

http://www.tomei-p.co.jp/_2003web-ca...enginekit.html

 

Is that one for the evo 8 though? The comments mention 1-7...

Terry S

 

bump