TheOtherEric

The whole point of the bhp/rwhp discussion is this: in England, it's standard to report dyno tests using flywheel horsepower, which they determine by measuring rwhp then doing a coastdown test to determine drivetrain losses. Those are added in to estimate the flywheel hp. Whenever English folks report dyno results, it's this flywheel hp. OTOH, in the U.S. we typically just report rwhp for aftermarket dyno tests, then let people guess at the drivetrain losses. On 911s, 15% is commonly used.

And as for the octane issue, remember that U.S. rates octane different from U.K. So he dyno'd at 99 RON which is about 94 to 95 [(ron+mon)/2] as used in the U.S. A touch higher than the 93 most of us use.

EDIT: ok you guys beat me to it!

simpateko

thanks for the RON vs MON clarification!
but this makes me doubt the claimed 35 hp gain even more.
i was starting to believe these results if using race fuel
but on pump gas?
here we go again, big hp for small money!

i guess the porsche factory didnt know how to map their 3.8 993 rs motor
because it only gets 300hp.

i bought a 964 from a hot shot, world famous race tuner.
he claimed 380 hp. in reality, more like 250 hp.
heads wouldnt stay sealed, ran like crap and filled the interior with exhaust fumes.
shoulda got a ppi.
$30,000 + later i had 317 hp.
all new 3.8 motor with rsr valves, motec, varioram and more.

understand my scepticism??

TheOtherEric

Simpateko- guys in England have been remapping their 993's for at least a couple years now getting substantial benefit. So he's certainly not the first. He's saying that all things equal, you'd get about 20hp from remapping, which IIRC is in line with what other English guys have been reporting. Would have to search to confirm.

I'd love to see the tech make a trip to the U.S.!!

Bull

Eric, when you say in the US "we" typically report rwhp, to whom are you referring? Manufacturers don't publish rwhp in the US. They typically publish bhp, which is neither flywheel nor rwhp. Most recently (2006) "SAE Certified hp" has been used by some manufacturers (Z06 Corvette).

In our tests, we find that 15% loss at the rear wheels is very optimistic with many 911s....so, I guess that is why people "assume" it!

TheOtherEric

Bull- I'm obviously referring to dyno shop testing. (i fixed my above post) I see your point, that mfrs report flywheel hp (actually measured at the flywheel), but the topic here is dyno testing and I'm not sure how we got on this tangent...

simpateko

92 octane at the pump on the west coast,
93 everywhere else.
i wonder why?

i doubt the tuner will get the same results if he maps for our 92-93 pump fuel.
if he maps for 95 and you use 92, big problems!
same story again, need to mix with race fuel to bring up the fuel quality
and it is not so easy to find on the road.

Bull

I'm with you...I don't know either. If I caused it...sorry, it was not intended!

Anyway, back to the original question...I'll take 317 hp, no matter where you test it!

Bull

We are just getting over losing 94 around here!

chris walrod

Except California, right? We get 91 here Then again, maybe its 91.99?

FlyYellow

well i got my union 76 that pumps 100 octane about 3 miles from my house (and on my way too). so i'm set. i typically mix 91 & 100. but if i did a tune, i would tune for 93, 94 with the idea that the knock sensor should be able to retard to handle 91 if i did a tank of 91 only....

that's actually a question i have. can the car's OBD I system account for 91 when it is tuned for let's say 93 or 94?

boris

Toga

Hi,
very interesting! I just changed my OEM cat for a cargraphic one, and the next logical step would be a remap. I'm a bit reticent though to have my original Eprom remapped. Did the guy who remapped yours gave you a cd with the original datas? Would it be possible to go backwards to the original settings?
Cargraphic proposes a remapped Eprom for something like 400 euros, but I didn't find yet somebody using that solution.
Thanks

nbooth660

I guess the actual figures are academic, but the increase is a real 20-25bhp and maybe a bit more without cats. There are many cars running a round in the UK that have had this mod, he's been doing it for at least 5 years I think. All ROW cars are OBD1 so no problem over here to remap a varioram.

I think it is reversible as he burns a new chip and keeps the old one std.

It's a shame you can't drive one of these remapped cars as you wouldn't think twice about doing it for the money...... the difference really id that noticeable.

Toga

Thanks nbooth660,
I like the fact that he burns a new Eprom. I might pay a visit on the other side of the channel next spring! Where did you do it? at 9M?

Caveman

Hi Toga,

There's quite a choice of people that do this. 9M seem an obvious choice though there are someof the bigger specialist Porsche garages plus AMD and I'm sure there are loads of others. This has been done over here for years which is why we are always surprised when other countries don't seem to do it. Absolute worst case you's get a copy of someone else's standard chip or have a to buy another chip but it's no big deal given how many cars there are out there. Not sure about the 3.8 option chip though?

Have you found any decent tunnels to drive through?! ;-)

Cheers,

David

Toga

YESSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS!!