Stock 2g IM= Stroker Power?!

[prophecymiller]

I recently ran across some amazing results from Dsmtuners- HERE (http://www.dsmtuners.com/forums/dyno-talk/375246-bw-s300sx-88-75-results.html). Notice this car is on a stock 2g head and IM! I compared this curve to a much more expensive 2.3 setup running similar boost and an FP HTA...they both had amazingly similar power curves...both made peak power and torque right before 6k.

I figured I would share as this possibly shows the 2g IM is better than most think. Why rev to the moon with a SMIM when you can have huge power and torque nice and low with a stock long runner intake manifold? The 2g IM may not flow up top, but it seems to make the same power much earlier as a SMIM. When you have almost 700hp in the midrange, who cares about top end....just shift to the next gear and get that power right back:D

What do you guys think? Am I interpreting these results correctly?

[prophecymiller]

This isn't directly related to the thread topic, but still compelling results none the less:

A thread on the Ecmlink forums- HERE (http://dsmlink.com/forums/showthread.php?p=447730#post447730) was addressing a problem with compressor surge under WOT. The OP was running a 35r, 1g head, JMF SMIM among other stuff. After swapping in a 2g head and Evo3 IM, the surge disappeared, probably from better flow at lower rpm's.

I sent him a PM asking how the new combo feels compared to the 1g head/SMIM, and this is what he responded with: "With this setup, I get better gas milage due to increase torque at mid range. Boost response is better between shifts. I don't have to rev the motor as high and the car is quicker and faster. "

That's what I like to hear;)

[thiazole]

I recently ran across some amazing results from Dsmtuners- HERE (http://www.dsmtuners.com/forums/dyno-talk/375246-bw-s300sx-88-75-results.html). Notice this car is on a stock 2g head and IM! I compared this curve to a much more expensive 2.3 setup running similar boost and an FP HTA...they both had amazingly similar power curves...both made peak power and torque right before 6k.

I figured I would share as this possibly shows the 2g IM is better than most think. Why rev to the moon with a SMIM when you can have huge power and torque nice and low with a stock long runner intake manifold? The 2g IM may not flow up top, but it seems to make the same power much earlier as a SMIM. When you have almost 700hp in the midrange, who cares about top end....just shift to the next gear and get that power right back:D

What do you guys think? Am I interpreting these results correctly?

I'm with you on this philosophy (and will add a little to it). If you have an N/A car, the only way to make your engine flow more air (without increasing displacement) is to turn more rpms (and you do this will bigger cam(s), higher flowing head and IM). With a turbo car, you can just turn up the boost. I know people claim to get more power with huge cams and a SMIM, but the caveat is that they make more power at the same boost. I think it is much less likely that they'd make more power if they turned the boost up all the way with both setups. The difference is that you will max out the turbo with less boost (but same airflow) with bigger cams and SMIM. If a turbo is only capable of 40lbs/min, you aren't going to get it to flow 50lbs/min with a higher flowing engine - it will simply hit that number with less boost.

The only exception to this philosophy that makes any sense to me is if a turbo is too laggy. If you aren't hitting full boost until 6000rpm and your cams are only good to 6500rpm, then you have a problem. Obviously, in that case, you need a setup that will allow you to rev much higher.

[Cloud]

Why do you guys think I stuck with the cyclone and evo3 16g on my stroker? :) Low/midrange VE is critical for a street car if you don't want to get bored. I guess some people like driving around above 4k all the time but it's loud and obnoxious if you are going to daily drive it IMO.

There are a couple considerations for tuning your VE curve with a manifold for instance, length, and diameter. Stock manifolds crap out up top due to length, not diameter really so downsizing to the 2g manifold is actually not that bad of an idea if you are trying to make peak power around 6k. Reduced diameter increases low end velocity and torque and if it isn't choking up top, it's not losing power. This is the 'you can go too big' principle at work, there is an ideal diameter for every application.

I watched enough people make their car undrivable by shifting the VE curve higher and higher till they hated it and sold it or turned it into a trailer queen. I went the other way and the throttle response was fantastic and fun to drive, I don't know why more people don't follow that path. I think people are just afraid of killing power by going to small because they don't understand how it works.

[drcustom]

The street car comment is what matters...but 700hp is hard to argue with in any setting.

What's nice about this is a car that makes some rocking power at 6k. If that's as high as you're going to rev it, then I wonder if there might be more power to be made lower RPM's with a slightly smaller turbo (or a stroker, but the more I think about it, the harder I think that will be to beat that curve). For a street car, that's way more than anyone needs and looks like a lot of fun.

"The 2g IM may not flow up top, but it seems to make the same power much earlier as a SMIM ... Why rev to the moon ... who cares about top end....just shift to the next gear and get that power right back"

If it's not a street car...and what you're really looking to do is stomp on the next guy then there is still an advantage to staying in a given gear. 700hp in 3rd gear is better than than 700hp in 4th gear. The torque multiplier available in lower gears is something that is easy to forget about. Sure you might not have snappy throttle response or be as fast off the line, but if your power range allows you to hang onto that torque (ie, delaying shifting) then all other things the same you're simply going to get to the finish line faster.

In short, that guy would go faster if that same power was just shifted to higher RPM's, but he would have to "rev to the moon" before that power was available. It really comes down to what your goals are. You're not going to use a chainsaw to carve a Thanksgiving turkey, and you're not going to use a kitchen knife to cut down a tree. If your goal is out-and-out racing there's a benefit to top end...but for a street car that guy has a pretty rocking setup.