I was wondering does anybody know how can i upgrade my 2004 6speed coupe ecu to give the 298hp that the 2005 have ?????

just as a note : i have done a search and could not find a answer thanx for all help

 

According to my dealer's service dept., there are no changes to the ECU and TCU for the '05 G35's. According to Infiniti press releases and some articles, they say the increase in HP for the '05's have come from internal engine modifications, variable exhaust timing or something like that, and a couple more small tweaks/changes; no changes to the ECU and TCU software are mentioned. My dealer's service dept. confirmed that there is no software update to "reflash" an '04.5 or '04 ECU and TCU; I will know next week for sure when I bring my car in for service and they hook it up to the Infiniti Consult II computer.

I was hoping an '05 ECU and TCU update on my '04.5 5AT Sedan would cure my upshifting problem (no delay now with GordGee's 10-wire GG system...the MM upshifting delay is gone now..yeah! ) where it doesn't always upshift into the next gear when I shift in MM mode...sometimes it stays in the same gear when I upshift in MM mode; when I realize it didn't shift into the next gear, I have to upshift again so it actually goes into the gear. After duplicating it several times while my Infiniti Service Mgr. was in the car with me, he agreed that this is a problem and it should work correctly all the time (it should upshift correctly into the next gear every time if within an appropriate rpm range), but he admitted they don't know how to fix it. We both thought that it might be possible to correct it with an '05 ECU and TCU update, but it appears there was no update in the ECU and TCU software...I guess we'll see next week.

 

That would be interesting to find out if Infiniti did / did not revise the A/F maps to get the bump in HP. Maybe they threw in a slightly more aggressive cam?

 

The 298 HP version of the VQ adds variable exhaust cam timing coupled with a higher peak HP point. The ECU would have to be remapped to take advantage of the different breathing and to control the exhaust cam timing.

 

Easy... get and install the Crawford High Flow Cats, the Crawford Plenum and a Z-Tube. You'll be out close to $1000 and you'll have as much hp (and probably much more torque) than the 2005's. FYI, with those mods I tried to scientifically extrapolate how much crank hp and tq I would have. We had a dyno day with stock cars and modded cars, did some simple calculations and derived that you'd gain 21 bhp and 10 lb-ft of torque (at the crank) with the mods listed above.

If the new 2005 have 298 bhp and 260 lb-ft of torque, anyone care to guess how much horsepower and torque increase these EXACT SAME mods will yield? I'm guessing the torque will just get back to the level of the STOCK 2003 and 2004 model G's and that the hp will go up ~10-ish at best...

 

As CKwik noted, on the 6MTs at least, the ECU programing has has to be different for the reasons he stated, plus the redline has now gone up to 7K. All these functions are ECU controlled.

And as neff noted you can get there with the mods he outlined. I would add the TS ECU reflash to his list. The reflash adds much to the mid range punch, and raises the redline to 7.1K. This allows you to stay in second till 60MPH. I never bump into the rev limiter anymore.

Lou

 

out of curiosity...is the 2005 coupe lighter than the 2004 coupe?

 

no !!! i actually saw the first 05'' 6 spped in fl. al has changed in interior console and steerin wheel and engine hp +++ no brembo's

 

The literature lists the '04 as being 3435 lbs curb weight and the '05 being 3512. So, no, the 6MT didn't lose weight it gained 77 lbs.

Lou

 

Where in the heck did the additional weigh come from? The wheels and tires plus some other changes?

 

I'm guessing the 19s added most of that weight. Different brakes, so there could be additional weight there.

So they bumped up the horsepower to accomodate the increase in unsprung wheel weight. I'm happy with my 04 6MT.

 

i am in love with the console ant the gauges in the of coupes I am planning to swap them. the look gorgeous !!!

 

You should see close to the same gains on both. The 2005 had exhaust timing changed and then ECU remapped to compensate for the changes. You'd probably gain abother 10 and 10 to those numbers for about $500 and have your ECU remapped by Technosquare (another good bang for the buck). I've heard Motorex built a 350 hp NA 350 Z so it is possible to get 100hp/L out of the engine.

If you want your 04 to get even more hp then get the JWT or Nismo (two or three other) cams, this should give you another 10 hp and you should be over 300 hp at the crank. I have seen at least 3 or 4 people with 260 + hp at the wheels on a 03/04 Sedan this is over 300 hp at the crank.

 

Most definitely there will be ECU changes for '05 6mt model. Your dealer is not incorrect, however. It sounds like they checked for the '05 AT models (MT models do not have TCU), which still has the same 04 spec VQ rated at 280hp.

 

But I have an 04.5 Sedan 5AT, rated at 260 HP/260 Torque, whereas the new '05 Sedan 5AT is now rated at 280 HP/270 Torque, and supposedly there were no ECU and TCU mapping updates. So, did the additional 20 HP come from the variable valve exhaust timing and improved cams, etc.? I find it strange that Infiniti didn't update the ECU and TCU software for the '05 Sedan 5AT...