I have a question. When was it decided that all 4bangers will make exactly 10-15 hp with an intake and exhaust?
Rhyno you might want to read this it contains some of those cold hard facts you are so found of.
I see the arguement often that an intake and an exhaust is only going to get you 10 -15 hp on a 4 cyl. That statement is so misleading that it is laughable. Here is a list of variables that will cause this magic number to be considerable different from one model of car to the next.
1. the size shape and design of the intake being installed.
2. the design, parts used, and extent of changes made to the exhaust.
3.Fuel management.
4.Timing and ignition management
5. compression
6.Restriction
7. power delivery threw the drivetrain.
I will hit on a few of these.
The HP achieved by different intakes and Exhausts is stupidly obvious. Moving on.
The computer management sytem in this car is a Delphi 64 pin Fuzzylogic set up that is on par or better than any car out there under $40,000 dollars. I will get back to why you get such great gear for so cheap later. The car has electronic ignition and varible computer controlled cams, and a very nice tune port setup and could adjust to and handle up to 4-5 psi of boost stock or a 70shot of nitrous stock. You are not going to do that with a Focus.
The great thing about this car is that when you change things like the intake and exhaust it doesn't keep running the same stock parameters it adjusts the fuel and timing to the changes.
Compression, any one with car experience knows one very effective way of making power in a N/A engine is raising compression. This is usually done by dished pistons and or changing the stroke length. Perfect example is increasing the stoke of a 350 small block by using the crank and con rods of a 327 to build a 383 stroker. Well a Forenza is up over 10.5:1 atmospheres.
Resrtiction, here is where we get to the ponies. A Forenza has the most restrictive intake and exhaust system I have ever seen in a car. Below is a pic of the intake and trust me the exhaust is just as bad. But the car still has the 2nd highest HP and Torque in its class. I hear some people say how terrible a stock Forenza sounds under full throttle and I have a response that while being some what silly gets to the heart of the matter. Let me jump on your back and strangle you with both hands and then you try to run and yell while im doing that.
You can be provided with a dyno chart that shows an Optra (same car) With to big of an exhaust, a considerably less effective intake and the UD pulley making 126 fwhp which translates to about 155 crank HP. With the differences in my set up I feel confident I am making between 10-15 hp more than that. Then add in the couple of HP I am making threw some minor mods like grounding. So with just bolt ons I am in a completely different competetive class than stock, and power wise on par with most of your sport compacts that are N/A and some lower level boosted cars such as the 170 hp Lacetti WTCC+r which is our car running some boost thanks to a factory supercharger.
Drive train has everything to do with real world performance, gearing is as big a player as power and I am here to tell you these transmissions are top knotch. The 5 spd is a Gertrag F20 labeled as a D20 to denote Daewoo. This is a sports compact performance transmission that you can find bolted to turbo engines in several makes. The auto while I don't remember all the letters and numbers is a very good GM design that is the auto option in all of those same cars. The trans has the same Delphi controll and does change modes to change the shift points to suit what you are doing. The auto will hold 1st threw 3rd gears all the way to redline under full throttle. People recomend shifting at 5500 rpms because the power and torque drop off after that but that is not how to best use a dohc engine. The power slowly drops after that and the higher shift point lets you engage the next gear at a higher RPM that puts you just below the max torque only using the power range of the gear. This is not a drag racing set up where you have to leave the line from a stop 3000 rpm below max torque. Dohc motors suck at the strip no matter what car they are in. But the Transmission makes up for some of this. Once you have left the line and break about 20 mph you will never drop out of the power range and a stock Forenza will only shift 1 time in a 80mph 1/4 mile run which a comparable speed to most stock compacts and well over half the V8 cars from the 60-70s. The only thing you have to fear is a car that is veryfast off the line. To use my own post as an example a V6 Camaro is no rocket off the line and once I got my rpms up the older car with twice the miles on the engine just didn't have a chance.
__________________
Last edited by dog : 07-24-2006 at 04:05 PM.
|
Linear Mode
