577HondaPrelude

Lets say you race in a series that has a max HP limit, and your motor can make more power than this max number without braking any rules, how would you lower your power to meet the HP limit?

1) Set your rev limit to a lower number so you never go over the max power number? Bleh!

2) Put on a narrower exhaust system that gives better low end power at the cost of high end power, making the power curve more flat?

3) De-tune your ECU to run a little too rich and with non-optimal ignition timing at high RPM to get a more flat HP curve that does not go over the HP limit?

4) Use an electric controlled throttle (like in the newer cars), and program the ECU to only let it go full open at the lower RPM’s, to get a flat HP curve?

5) Maybe put an electric servo motor on the duel runner intake butterflies (if you have VTEC), and program it to keep the HP curve flat!? Sort of like a controllable restrictor.


Anyone else have some neat ideas?? If there was such a rule in a series, for arguments sake, it looks like the best engine to run would be one that is built to get as much HP as you possibly can and then come up with a neat way to get a flat HP curve.

Egezzy

iTrader: (2)

just dont run nationals and go ***** out.

slammed_93_hatch

header/exhaust that is built for mid range and not top end.

Works really good.

unusual71

^ seconded. If the limit is only on HP then broaden the torque curve and lower the peak a bit. Area under the curve ultimately dictates how fast the car is, not peak numbers

A Blue Lude

Cam gears if they're free.

Lo-Buck EF

I would go to the dyno and detune it and try to pick up some mid range.
-or-
lower the limiter.

steronz

Get a turbo. I believe the SRT-4 did something like this, or maybe it was a similar car. Hit max boost early on and then the boost would drop off as the revs climbed to keep the torque constant. I think it was an effort to protect the drivetrain. You could effectively do the same thing for horsepower, so you hit max hp at 2500 rpms and then just start bleeding off boost to make the hp curve flat.

Lo-Buck EF

Forced induction isn't legal for the class he races in.

steronz

Oh, I thought we were playing hypotheticals.

Battle2.0Eg

Adjustable Camgears
Back up the Centerline

Lo-Buck EF

nope, this really happened.

The Destroyer

Is using a restrictor on the induction end any better than exhaust? Much like the sae guys that have to work around the restrictor to make power.

vbspec

Yup
1) Spend just as much to build the midrange as you would have for top end
2) Detune ecu if nessisary...
3)??????
4) PROFIT

577HondaPrelude

It is hypothetical. With a slight ulterior motive to illustrate a point that giving a motor a max hp number does NOTHING to lower the cost of a build. If the powers that be want to do this type of thing in an effort to keep real cost down, the more logical thing to do would be to limit the average HP from MaxRPM to (MaxRPM – 4000). For example my engine’s MaxRPM is 8400 so my average HP from 4400 to 8400 PRM should have a max average HP number. Two cars with the same average HP in the usable power band are MUCH more equal than two cars with the same peak HP.

heel_touge

i think the electric throttle is the way to go. you can tune the motor safely without any adverse effects of running too rich. When and if its time to up the power, you don't have to go swapping out exhaust/intake pieces.

+1 for Ease of use and ease of adjustability.

EDIT: forgot about the RPM adjustment one. In this case you would have to putz with all of your gearing to be competitive on certain tracks. so you're still doing a lot of extra work.

Sr420Det

an electronic exhaust cutout that opens down low and closes up top haha

slammed_93_hatch

if you go for ease of use and adjust-ability, youll get left behind by the competition that goes for the most advantageous...

JohnW

^This.

Sorry, Walt.
Really, I am.

Historically when do-gooder cost controls attempt to limit one thing or the other... it backfires. It will cost more and become a PITA to #1. Stay legal. #2. Be competitive.

The guys with the time, money and tricks will only widen their advantage.

Sometimes things can go so terribly wrong within a rulebook that the only fix is a total reboot. If this was a real series you're talking about...

racebum

hp limiting just seems odd. i mean how do you test the hp ? does everyone dyno right before the race? what makes more sense is to limit air intake. everyone running a 50mm restrictor on the TB makes sense

if for some weird reason you're in a hp limited class the motor should be designed around it. if for example we're talking about a common motor like the b18c and the limit is 180whp, that's not really a bad thing, it just means you won't need to spin to 9500 which prolongs engine life. in my opinion anytime you can keep rpms down it's a good thing. that said i would experiment with different cams until i found a set that produced the best overall powerband. in this 180whp example i doubt the engine would stray far from an oem type r. the performer x would be the manifold of choice since it offers a longer runner and still supports a fairly high redline. i would guess the X could be tuned to give a few hp and ft/lb in the midrange fairly easy. probably experiment with headers too starting with something like the toda 4-2-1 and see if the midrange looks stronger. more compression also could help but it isn't going to be hard to run past 180whp even with oem itr cams if we get too crazy.

slammed_93_hatch

If in this mythical series, there was nothing that needed to be fixed. Things, the way they stood in the rule book, where good (in this mythical series).

Perfect? No
Could they be improved upon? Sure, there isn't a perfect class, even in mythical land.

Two (mythical) people built motors that produced more then most (mythical) people thought they should make. They tore them down, and found one to be legal.

(mythical) People got upset and started saying there was thousands and thousands and thousands of mythical dollars into these motors, which BTW isn't true in this mythical situation.

So you get this, in the mythical series, a "fix" to a problem that wasn't there in the first place in a mythical series.

JohnW

It sounds as if "racing" isn't the priority in this mythical series, Jimmy. One could assume, the focus seems to be more social engineering and fairness rather than motorsports in it's natural state. You know, eveyone deserves a throphy kind of thing.

I certainly could be wrong... as this is just a hypothetical.

slammed_93_hatch

In this mythical series I like to say it's turning into that "no child left behind" program.

racebum

mmm, i don't know about that. nascar is so regulated hp is extremely close across the field. what it does do is come down to the driver with no real advantage in the car

typeR_s

Do they run your car on a dyno when you are teched in? If not why not just trying to go to a lower reading dyno?
I'm not agreeing, and or incouraging cheating. But I know from first hand experience that not all dynos read the same. And if you are on a high reading dyno like a Dyno Jet, you might not have as much power as you think compared to the rest if the field..

GSRCRXsi

guys, this new rule for this (mythical) race series only applies to (mythical) Nationals, not every event. at the last (mythical) nationals event, they had a dyno available for tuning purposes, my guess is that it will be required at the next (mythical) Nationals.