Sweet this is some good information... I am definitely going to be getting the BRP around December time.

I am going to have 3" dual exhaust, J's header, the BRP SC (ported) and of course a clutch!! Do you think I will need to buy a fuel pump and injectors??

Oh yeah, I know the kit comes with the battery relocation kit, but is that the stock battery or do you have to buy an aftermarket one?

Sorry if these are newb questions, I'm just trying to make sure I have everything figure out. thanks

 

All good questions...might want to try the BRP forum or just wait till one of the BRP boys check this thread.

 

Wouldn't it be more meaningful to compare the area(s) under the torque curves? I think that would show an even greater difference. Could you calculate the area under the curves for the various systems and rev ranges, and post the results?

 

[QUOTE=RED MX5,Mar 9 2006, 09:11 PM]Wouldn't it be more meaningful to compare the area(s) under the torque curves?

 

yep, area under the torque curve is a more telling story.

 

To be honest with you. You can almost disregard the torque curves. You feel acceleration (change in speed over a period of time), and acceleration comes from power, not torque. Of course you need torque to make power, but its the power curves that are more meaningful as they have the "per time" component necessary the acceleration consideration. This is what you feel.

Good example: Lets say you have the "magic engine". An engine with a torque curve COMPLETELY flat from idle to redline. If torque is so awesome, the end all be all of what people look for in an engine, and what you "feel", then you probably think that your car accelerates at the same rate at 4500 RPM as it does at 9000 RPM. Of course this is hardly the case. You don't feel torque, you feel power, which torque creates.

Hope no one pulls out the F=MA argument . Of course acceleration relies on torque, but trust me, its the power you feel.

 

The conclusion I draw from all this is that the BRP SC is what most of us were really after when we bought a Comptech/Vortech SC, and what everyone who hears we have an SC is expecting. Even yesterday an old friend and S2000 owner asked why I got rid of the Comptech when SCs were better for low end.

The one part of this equation that we're not really taking into account at this point is availability. You can't buy a BRP at present, and you can't be 100% sure of the final price either. When the product is on the market and any bugs squashed that is the time Comptech/Vortech need to be worried.

And then there are turbos. The common misconception about turbos is that they are A) laggy and B) better for top end. In many cases this is true, but it depends on the turbo. For example I expect you would get very similar results to the BRP with a GT28 ball bearing turbo. It would be spooled before 3000rpm and provide whatever boost you limited it too (within reason) all the way to redline.

Me, I went with the LoveFab GT3071R turbo because it was a mild system (very similar in performance to the BRP) but has as much potential as I could ever need (famous last words). I mean, I can control the boost and hence power at any point along the curve with nothing more than a GM Solenoid ($30). If I want low boost in low gears, no problem. If I want to trail off boost at redline, done. And if I want 16psi somewhere along the curve, that's doable too.

I think the BRP will be a success and I would love to try a car with it. There is certainly a market for it and I foresee a bunch of used Comptech/Vortechs on the market shortly.

 

AusS2000 could not have stated it better.

Assuming all things play out as planned. the BRP kit is going to be rediculous. I put myself to sleep at night thinking about it. It really is a middle ground between the Comptech/Vortech offerings and the Lovefab turbo kit. Obviously closer to the Lovefab though

Aus, your kit probably has a nearly identical feel to a BRP kit. At least from published dyno curves. How does it feel compared to stock and compared to a centrifugal kit. I assume you've experienced the latter?

 

Slim, I took a while to respond to this because I wanted to check my facts and think about it some before opening my mouth. The laws of physics are often misused, but outside quantum mechanics, they always apply. When they don't seem to apply it almost always means that we have misunderstood something. Please understand that it is not my intent to start a debate. The laws of physics are not debatable, so all any of us can do is explain them. If I get any of it wrong, please feel free to correct me.

If F=MA then A=M/F, so we have to accept the fact that acceleration is produced by force. We also have to accept the fact that the measure of force in this case is torque. The confusion comes in when flywheel torque is confused with torque at the contact patch. It is actually the torque at the contact patch that produces acceleration. A given amount of torque at higher RPM's (which equates to more power) allows numerically higher gearing, which yields more torque multiplication. We do not feel power or torque. What we actually feel is acceleration. If horsepower could be felt, it could also be measured with an accelerometer, but we have no way to measure HP directly. That's right, HP can't be measured, it can only be calculated, so obviously it can't be felt. HP is always calculated from either wheel torque and revs(on the dyno) or acceleration and mass (or revs, with data loggers).

A given amount of torque is better at higher revs because of gearing. HP just gives us a way to capture the effects of torque and optimal gearing into a single number.

Here are two links that explain this all much better than I can. PLEASE take a moment to read them both, especially the last section of the page pointed to by the first link.

http://www.g-speed.com/pbh/torque-and-hp.html

http://www.houseofthud.com/cartech/torquev...shorsepower.htm

The advantage of power only comes with gearing.

Now that we're all on the same page, I'll try asking my original question again. I agree that the averaging method you used yields the approximate area under the power curve, but think about that for a minute. HP is calculated based on torque and revs, and when you average HP over a range of revs you are integrating with revs a second time. For anyone with a background in physics, math, or engineering, or for that matter for anyone who understands the physics involved, the area under the torque curve (or using your method, the average torque) is much more meaningful. Because the gearing is the same in all cases the torque multiplication will be the same, and any changes in acceleration will be the direct result of differences in torque at that point in the acceleration curve. A=M/F always applies. There can be no exceptions outside quantum mechanics, and if you can find one, you'll be famous.
Soooo, wouldn't it be better to calculate the area under the torque curve? (That was my original question. )
(Now I wonder if it was just rhetorical. )

 

The torque and hp diagram give you the same information. Comparing the area below the hp curve is the same as comparing the area under the torque curve (reason: hp is torque*rpm AND you have rpm for the "X" axis on both diagrams)

Actualy hp diagrams when you have the torque diagram is useless because the torque diagram gives you the same information in a more straightforward way. All you need is the torque diagram and peak hp number (which can, if unavailiable, be calculated from the torque diagram) to get the full information.

In order to make comparisons between different engines it is important to emulate the powerband of the one of the two over the other.Peak rpm minus idle rpm is the powerband. Unfortunatly dynos don't measure from idle but from higher rpms (why really?) so you make a choice of which rpm level (as a percentage of the powerband) you will to choose to use for the comparison. After you get the dyno of the first car from this rpm over to redline,then you strech (or shring) the dyno of the other car (begining from the same rpm as a percentage of this car's powerband and ending to redline).In this way the begining and ending of both diagrams on the "X" axis is the same. That is the only way to accuratly compare two engines. It should be done so that the BRP 2.2 liter is 100% comparble to the other FI engines.

Edit: This emulation can be applied only to the hp diagram because it removes rpm from the equazion.Rpm is indegrated into hp so that is ok. It can be done to the torque diagram but that would need a second emulation for the "Y" axis us well (the streching/shrinking as a percentage on the "X" axis used in the emulation on the second car should be removed/added as a percentage to the "Υ" to this car's values respectivly)

Edit2: Reading back my text, i bearly understand what I wrote