CAlexio

i just looked that up.. thought it was an aftermarket part you were referring to.. then realized IT WAS an aftermarket part.. but for your body not your car. I clearly need to get with the program.. didn't realize this was a thing.

user1029

I've seen those commercials a few times by that I mean every commercial break for NFL games

BGB Motorsports

I don't want to make any claims until this motor package is in a car, has been dyno'd AND has seen at least a weekend's worth of time on track. I am not trying to get anyone falsely spooled up but it's just that if we are going to survive i need to stay ahead of the development curve. Now that the motor we always believed should be in the 981 comes in the 981, my combination of ADD & OCD has forced me to push my dream project to fruition so that we can keep offering something that makes folks want to send us their cars. We try and reinvent ourselves as much as possible with what we can offer and this is one of those things!

My own personal opinion is that if the kit made 10 more HP and 25 lb/ft, it would be a huge success. This car needs more torque and if you get it to 991 levels of 325lb/ft, and were successful with the stroke upgrade and being able to deliver more lb/ft, with that would come more acceleration potential. Ultimately i would like to do this upgrade to a car with the Power Kit heads/cam/manifold and all of our Stage I upgrades to see if we can really achieve near 475 crank HP. While it is just a goal and while i am not making any claims yet, I have expectations of getting there. UNTIL i see the parts on the car and being tested though, it's just a horizon.

GrantG

Usually adding 200cc has the opposite effect (~20 to 25hp and ~14 to 17 ft-lbs)...

BGB Motorsports

Don't you need to factor in how the 200cc was added? If it was a bore increase, power would be increased more than torque; since it's a stroke increase, torque will increase more than power, no?

GrantG

Displacement of an NA motor is very nearly proportional to torque within a very narrow range. The main variable is compression ratio. I think the most one can expect with a motor like the 9A1 in the GT4 is about 85 ft-lbs per Liter (17 ft-lbs per 200cc). Geometry plays a role, but this is the theoretical max with pump gas and stock compression.

You may make a little more or less than that at particular points on the graph where there is a breathing problem or enhancement in the stock system. I think averaging 16 to 17 ft-lbs increase across the rev band would be a reasonable expectation.

In general terms, you're increasing displacement by 5.26% (going from 3.8 to 4.0), so you're increasing torque ~5.26% too...

Maybe aim for 4.2L?

Generally adding displacement with bigger bore lends itself to greater HP, since it does not affect piston speed and you can keep a high redline.

Adding displacement with stroke adds torque (proportional to displacement increase), but sometimes sacrifices max HP gains from the extra displacement since the higher piston speeds (at a given rpm) causes one to lower redline targets (e.g. 9k in GT3 vs. 8.8k in RS - redline still above peak power rpm so makes the full 25hp more)

BGB Motorsports

I know this is going to frustrate more than it is sooth but you guys said you wanted more power so...

CAlexio

what is her name?

OMG.. this is awesome.

Ferrarisimo

We need video, stat! What's the redline of the 3.99L?

RealityGT

user1029

9k

via Imgflip Meme Maker

gt3rs.

tasman

John,

You are an evil man! I don't even have my car yet and it already seems inadequate.

TRAKCAR

The std GT4 will go 8800...
Seen Walter Rohrl do it, I even took a screenshot of it:

user1029

I'll be changing my license plate to "HNR RLL" if I get the conversion