felix_is_alive

Ok here goes , i will probably take the car to the dyno this weekend or the next one , i am a bit busy so i didnt have a chance yet
But , i dont know if anyone has any experience with the apexi rev-speed meter , its like an on-board dyno , uses computer outputs (mph and rpm) , compensates for wheel spin , rim change weight change plus can be calibrated for power loss (wind resistance ,tire friction etc)

I happen to have one of these units in my car , with the optional G-sensor , i dont know how accurate these things are but i tought since i have it why not try it (its kinda like a G-Tech)

Even if its not dead on accurate it could/should give a aproximate indication of how the car is running ...i figure

Well to sum it up i tested it today , and i pulled 477ps (jap version of HP) @ 7066RPM , i let the throttle go because i feared a lean out (i still dont have my fuel pressure regulator installed , i know i am lazy )

477 is about 475Hp , could this be correct i am running 10psi of boost do these numbers make sense , my tune is still off since its a bit hard to drive and tune at the same time without wrecking the car (when i get to the dyno it will be done properly)

Do those numbers make some sense ?
What do you guys think? any inputs are welcome

Evil Aviator

If it's like the G-Tech, it will be precise but not so accurate. The bottom line is that it works well for a tuning tool if you look at the trends, but the numbers may not translate to dyno numbers or 1/4 mile numbers very well. Actually, O2 sensors and dynos also suffer from a lack of accuracy, but people still use them to tune successfully (as long as they don't go by numbers they see on the internet, lol). To increase the accuracy of your numbers, be sure to take a reading by driving the track in each direction, then average the numbers. This method will help compensate for wind and grade.

PS is actually German metric horsepower, but it was adopted by other countries like Japan. Multiply PS by 0.98632 to get SAE horsepower, which means 477PS = about 470.5bhp. Anyway, like I stated earlier, that number may not be accurate.

Sounds a bit high. What kind of porting and intercooler does it have?

felix_is_alive

EVIL!!!!....whats up man , where have you been , haven`t heard from you in a while on the forum , i guess i got the correct man to answer my question
ok here goes
agressive large streetport,13b housings (also large street port) , large apexi front mount (those delta fin core things), turbonetics T76 Q trim , with 1.15A/R on hotside
Engine is also doweled/pinned

I also think its a tad bit high , altough i do feel that the car is fast ,even compared to my old 2 rotor @20psi
Also this is kind of a G-tech unit , i think the readings i got where the peaks though so my peak rpm was 7066rpm and my peak hp was 477ps

Evil Aviator

I've been kinda busy, but lately I have had some time to post on the forum while surfing the internet for stocks and houses. Man, stocks are so much easier to deal with.

I'm not sure if I really answered the question, lol. Once you put the car on a dyno you can get a better idea of how your rev-speed meter output relates to the dyno output.

Swagging the numbers on my uber Windows calculator I get about 450ps, so maybe that Apexi thing isn't too far off? Of course, I could be way off with my swag because I guessed at too many variables. It would be interesting to see what the dyno says.

felix_is_alive

i did a checkup on this , and i noticed i screwed up somewhere in the setting , i entered my car weigs 1700kg , wich is a bit much , on the sticker on the side it says 1456kg i set the setting today at 1580kg , wich should be the differance youre talking about , i didn`t get a chance to test it tough .
during the week i am pretty much stomped with work , i will see if i can try it later (if i get a chance ) and then we`ll compare it to the dyno ...should be fun right?

Evil Aviator

It should show about 443ps for 1580kg, and about 409ps for 1456kg. The numbers will be about 1% lower if your region is warming up like mine did today. I like warm weather, but engines don't.

Yes, that will be interesting.

streldoc

iTrader: (1)

I would say the numbers are close. You can see by the boost tracing that peak power was at about 11 psi boost, as the controller is averaging down. This is our pump gas dyno pull. Specs on the the engine at www.7parts.com. Your turbo is bigger than our GT40R, so you should be making more power at lower boost.

felix_is_alive

Erik whats up , once i get to the dyno i will also be playing a little bit with the timing , or at least be looking at it carefully , looking for room for improvements
BTW the timing maps you send me where very helpfull , i didnt knoe you where running a GT40R though
Oh and by the way , nice graph , pulls nice huh ?!