so what you are saying is buy another head, have a talented shop weld some material to decrease chamber size, and crank T3H VTAX UP


fuckit, Ill grab another motor and go crazy learning what these bad boys can do. Im out the military soon, so I can finally actually afford to have some real fun


Im not concerned about the detonation. Thats too easy to keep an eye on and adjust accordingly.

 

Well here's the big problem with detonation control techniques.. spark timing is directly tied to cylinder pressure and where that pressure builds/peaks/falls with relation to rod angle.. this is what determines how much torque you will make.

If you are familiar with this, then no doubt you know how horsepower is derived from torque.

This is a series of pressure profiles related to spark advance/delay vs crank angle:


So dependent upon your R/S and Rod angles, where your pressure peaks is critical:




If you are running a given fuel at stock compression and are running into to knock intermittently, and then bump compression yet higher you may very well have decreased how much power you will potentially be able to make.

Higher compression with the requirement of retarded spark events and running extra fuel to fight pre-ignition/detonation is going to make less power per unit fuel/air mass as well as less power overall.. is what I'm trying to illustrate.

These little guys can handle a lot of power.. But you need all components of the system compliment each other.

It's all about getting the most out of this cycle:


With as little fuel and air as possible. So if you are forcing yourself to not only delay timing but reduce the proportion of oxygen to slow the burn because of your fuel limitation due to heat from greater compression you are sacrificing fuel, power, excessive EGTs potentially damaging your exhaust valves and catalytic converter.. but you are increasing piston side loading on the bores which will lead to Out-of-round and slapping.. which leads to increased blow-by.. which will put more combustion gasses into the crank case, contaminating your oil faster, increasing crankcase pumping losses, putting more blow-by out the PCV into the intake, which will put more build up in your intake manifold and ports... etc and so forth.

It's a vicious cycle

 

Angular acceleration and displacement, FTW.

 

Off topic Proofing (SI):

T=F*d

P=(F*d)/t

T= Torque (lbf*ft)
P= Power (hp)
F= Force (lbf)
d= Displacement (ft)
t= Time (min)

 

Do it! Sleeve and punch! I respect all motor. Like DSM has pointed out there is a lot to consider; all though the gains CAN BE minimal, the work, time and research is what has my respect.

In Super Gt the GT300 class Subaru made 300 hp out of a 2L. But at what (financial) cost? I bet a the block is a one off and machined from a solid piece of aluminum for starters...

If it's for hobby purposes I say run with it. But if you eventually want to race the car; choosing what class you want to run in is the first decision, and mods are secondary. Modifying is fun, but its more fun to get use out of them. Mods can put you class against cars you may not want to run against.

 

Haha. You make creating horsepower sound so easy!

 

Yar, didn't think just throwing in high comp slugs was a good idea, ECU would retard timing from knock sensor unless maybe you're running 100 but that's more trouble than it's worth.

Which is what DSM is trying to say I think in laymen's terms

 

Well, you dont need a one off block to make great power. I believe I saw an F22 motor (old accord) turned into a fire-breathing 320whp NA monster. I think it ended up around 2.45 liters or so.

Cherynobil K24 was built to 2.6 liters and 352whp and something like 311wtq

 

^^ That's awesome. The area (power) under the curve must be huge.

Like I said "the gains CAN BE minimal", but they aren't always minimal.

 

To generate big power figures NA you need to be able to wind it out. This takes more than just raising the rev limiter.

320whp/2.45l = 130whp/liter
352whp/2.6l = 135whp/liter

That would amount to ~200whp from our 1.5L. Which has a fraction the aftermarket support, and only the L15A1 even has a tuning solution that would enable this.

The drag cartel motor is running 15.5:1CR on alcohol, with 106mm crank inhaling through ITBs on a custom radical Web stroker cam and modified lifters. That large crank throw matched with a high lift long duration cam to deal with the absurd piston speed and dwell is what accounts for the torque that keeps them from having to spin to the moon. Super stable Alcohol fuel to take advantage of the compression, while creating a larger exhaust volume than gasoline and greater energy per unit fuel mass is a big component as well.

This is not a configuration that you would run on the street, as it will be beating the piss out of the bores and bearings with a 106mm stroke among other issues.

The F20C/F22C came from the factory with a head and cam pair that make peak torque after our redline.

Not trying to be debbie downer here, but lets be honest. For the cost and effort required to pull ~130whp out of the L15A1/7.. you could buy a used base C5, throw a turbo'd junkyard 4.8/5.3 in it and make a reliable 800whp in a much better platform and have enough to pay insurance left over while saving hundreds of hours of testing and tinkering.

If you are building a competitive program for a specific series it might make sense.. to do this in your DD/Family hauler it would break nearly any budget that would be involved in these cars as a hobby in the first place.

 

More popularly known as the "cost:benefit" ratio.

 

~$17k after tax to buy turn key, which is easily what you would spend on a 200whp NA L15 build out:


300whp, 6MT, RWD, decent on gas and reliable.

Cars for Sale: 2000 Chevrolet Corvette Coupe in Libertyville, IL 60048: Coupe Details - 362837613 - AutoTrader.com

Or, the route I would go, find a $7.5-11k rolling shell with a bunch of goodies you can resell, here's an example for $8k:
Ls1 Corvette C5 Roller FS - LS1TECH

Then you only need:
$2500-4000 for lines, fittings, pipes and fab
$900 for EFILive V2
$600-1200 for a T6 frame journal bearing turbo
$500 for injectors/regulator
$500 for a big fuel pump
$300-1200 for a 4.8-6.0L out of a salvage yard
$300-900 for an intercooler (Air/Air or Air/Water)
$300 for a 50mm BOV
$300 for a 60mm wastegate
$150-200 for a turbo cam and springs

 

^But what if i'm under 50 years old?

jkjk

Vettes are cool.

 

So, clearly, from a cost-benefit perspective, a pure NA build is not a good idea for our Fits. What if we were to add boost to the equation? For simple folks.

Setting a 200whp goal, let's say I got a Sprintex SC and reached 170whp. Would it be a simple matter to get the remaining 30whp?

 

I'm nearly there, so no problem here.

 

From what I remember of the compressor map published for the unit Sprintex is putting on the GE, 200whp would be at the very upper bound of what it can provide on paper.

But you would need a pulley smaller than what they offer to run the boost needed to put you in that part of the compressor map with our stock displacement/VE.

~145whp is so far what an actual dyno visit has shown the kit makes currently on one owner's vehicle.

A well matched turbo would be more efficient in several respects and could be made to produce better mid-range and top end. But install is slightly more complex.

 

I'm just over half that old

My next project will likely be a redneck mobile no non-sense Fox Body (87-93) Mustang radial tire, mostly a strip machine that will occasionally see the street... Mini-tubbed on 28s with a big single turbo LSx pushing through a Lenco box.

Something along these lines:

 

Good lord turbo is bigger than L15

Acquire 4cyl LX notchback and proceed to replace everything

 

char10

 

I was mentioning a F22 FWD setup. Not the S2K motors

horsepower per liter means little to me in terms of performance. I want TORQUE!!! Torque means fun!!! lol