99 carerra rebuilt engine with mods... Curious about projected horsepo

[demarconstruction]

Hi guys, looking for any input or comments on what power/performance I should expect from a new rebuilt on my 99 C2 3.4 to a 3.8 liter Jason from UFO Motorsport in CA performed the work . Included in the rebuild was Nickies , raised compression to 12:1 polished ports(350hp) Ipd plenum ( 28 hp) , k and n air kit( 23 hp) NHp full exhaust system ( x51 headers, 200 cat x pipes w/ mufflers 30+hp) horsepower listed after each mod is the advertised increase . I've read that these hp increases are not realistic but would appreciate the input from this forum as I will eventually have the car dynoed once Ecu is tuned . Thanks in advance

[valfam]

Did you ever get the motor on the Dyno? I always said it's easy to make a slow car faster but to make a fast car faster is not easy. I think HP ratings like they advertise you can not just add one and another for your total HP. I don't know just my thought.

[Cloudsurfer]

It doesn't work like that, i.e. 350 + 30 + 23 + 28= 431. First of all, a K&N filter is not worth anything, and I would never run one on any car with a MAF. The IPD plenum helps, but it's not 28 ponies of help. Likewise, exhaust does not get you a 30 HP gain.

My LN sleeved 3.8 at 12.5:1 compression with forged everything, ported and cleaned up heads, and headers/ no cats/ free exhaust did 330 at the wheels, which is right about 390-400 at the crank.

There are gains to be had on a built motor with custom software.

I highly doubt you will be making 430 with your setup.

[Silver_TT]

Sorry to bear bad news but after all your mods and ECU tune, I doubt there will be much difference. On the naturally aspirated engines there really isn't much HP left to squeek out. Ya, maybe you can get an extra 10-20 if you spend some money, but it will be a marginal return for the amount of money you will have to spend and I don't think you will notice too much driving. You're definitely not getting anything extra with an air filter. If power is what you're looking for, get a Turbo.

[JoostE]

Just curious; if you are able to add so much extra power and torque to the cars engine, what will that do to other parts of the car like the gearbox, brakes and so on ?

Do you upgrade these also ?

[Silver_TT]

Adding torque and power often means various components need to be upgraded to accomodate the extra stress that will be placed on the vehicle. This is one of the main reasons it makes a lot more sense from a financial perspective to just sell the naturally aspirated vehicle and buy a car that was designed to take more stress, like the Turbo, if that's what you're looking for. Moving these cars too far out of spec can end badly. The components of a NA 996 are not built to take an extra 100+ HP. Some will be lucky and never have issues.......others not so much. When things do go south, it can be catastrophic and very expensive.

Edited September 3, 2013 by Silver_TT

[Loren]

Adding torque and power often means various components need to be upgraded to accomodate the extra stress that will be placed on the vehicle. This is one of the main reasons it makes a lot more sense from a financial perspective to just sell the naturally aspirated vehicle and buy a car that was designed to take more stress, like the Turbo, if that's what you're looking for. Moving these cars too far out of spec can end badly. The components of a NA 996 are not built to take an extra 100+ HP. Some will be lucky and never have issues.......others not so much. When things do go south, it can be catastrophic and very expensive.

I could not agree more - well said.

[Cloudsurfer]

Sorry to bear bad news but after all your mods and ECU tune, I doubt there will be much difference. On the naturally aspirated engines there really isn't much HP left to squeek out. Ya, maybe you can get an extra 10-20 if you spend some money, but it will be a marginal return for the amount of money you will have to spend and I don't think you will notice too much driving. You're definitely not getting anything extra with an air filter. If power is what you're looking for, get a Turbo.

There's plenty of difference when you add an extra 400cc and bump compression an extra point and clean up the heads. Like I said, my 3.8 made right around 400HP. It's also infinitely more reliable than any of the stock motors are.

Also in agreement, the air filter and other bolt ons aren't worth much.

These cars can take some extra power, but you also have to be smart about it. I wouldn't launch any of these cars- bone stock or modified- as if that's what you want to do, you bought the wrong car. However, feeding in an extra 75hp in third gear smoothly isn't going to hurt anything. Thankfully, these cars already have plenty of braking capacity (with good pads), and if you've gone this far with building a motor, it's safe to assume you've already upgraded the suspension.