stinkin slow car

[onephatz]

got a 75 280z with a '82 turbo motor in it. 3" down pipe w/ 3" exhaust cold air intake k&n filter, running stock boost 6psi. front mount is on the way but for now its gotta be stock.

 

all I gots to say is man this thing feels slow. Why? I'll tell ya.

 

Had... a L28 with flatop pistons w/ N-42 head running 10:1 compression with everything else the same except it had a 2.5" presbent exhaust.

that motor had a real attiude. I was running with stock awd dsm's.

 

dont really know yet how slow it really is. gonna be going out tonight and next weekend with the dsm boys to see how she runs.

 

bahhhhh

 

jesse

[BayAreaZT]

Do you have a boost gauge hooked up verifying you're getting boost? Shouldn't feel slow at all even at stock boost level. Check all the usual stuff like timing, plugs, vacuum leaks, etc. You may have to get some electrical contact cleaner and clean all your connection especially at the AFM and ECU connectors. Made a huge difference on the way my car drove.

[onephatz]

just figured out why

 

when to http://www.turbofast.com.au/TFcompB.html

 

seems with a stock turbo psi your getting around 9:1 compression

then when you up the boost to like 14psi your gettin like 12:1

 

that's more like it.

 

so.....

jesse

[mobythevan]

So you saying I can build a 12:1 non turbo engine and have roughly the same horsepower and torque as a 14psi turbo engine.

 

 

Your 10:1 engine must have been making more than 180hp and 200torque if the stock turbo engine feels slow. Which could be true, if not you have something wrong with the turbo install.

[Guest bastaad525]

When I had my stock N/A motor, N42 head, flat top pistons, running 10.3:1 compression, with a mild cam and SU's, headers, etc, in my same 240, I was putting down 170hp to the wheels, and 170ft lbs of torque. A few guys have dynoed bone stock 280zxt's and come up with numbers closer to 140-150 hp, and about the same 170ft lbs of torque, so when I switched over to a turbo motor at first it wasn't much of a change... indeed the turbo motor 'felt' slower. With your 3" exhaust you should be putting down a bit more power, one guy, Jeff, with a 280zxt bone stock saw more than 20 extra hp JUST from going to a 3" mandrel exhaust. Still, it is possible, depending on how worked your N/A motor was, that it was pretty close in power to what your stock turbo is running now. It has nothing to do with compression ratios and the theoretical compression that boost adds. It's also the nature of the turbo motor, in that it doesn't react instantly, the turbo has to spool up... a stock T3 has very minimal lag, but the way the throttle responds is noticeable vs. a tuned high CR N/A motor, and will feel slower, even though it's more torquey. THAT is where you will feel the compression difference.

 

But all that goes out the window as soon as you turn the boost up. Turning the boost up a measely 3 psi netted me about 50hp and 50ft lb increase at the wheels with NO OTHER MODS (200hp/234ft lbs), and I'm not even running an I/C. There is NO doubt that my turbo motor is now faster though sometimes it still feels like I slug when I dont drive it "right". You just gotta be conscious of that turbo, and keeping it spinning when you know you're gonna want the power. Cruising on the street in 5th at 2000rpm... just isn't gonna work. And launching is a whole nuther deal too. With my N/A motor, I used to just hold the revs at 2500rpm, and dump the clutch. The tire would spin thru all of first and a nice long chirp into second, and a chirp into 3rd. If I try that with my turbo motor I will bog badly. To launch fast in a turbo it's best slip the clutch out to help build boost off the line... it's a technique that's been pretty hard for me to get the hang of. In my N/A I was able to consistently run 0-60 in about 6.5 seconds... I know with the extra power and extreme extra amount of torque I'm pushing now in the same car I should be good for 0-60 in less than 6, but because I suck at launching it best run so far has been like mid 8 seconds!!!

 

it's a whole nuther beast to be sure... but you'll get used to it and once you crank the boost... you'll never look back