Ecu Reflash & Raising Rev Limiter

[MaXiMuS007]

Has anyone here with an early model V35 had experience with rev limiter/ECU mods like this one:

http://www.6mt.net/forum/performance-mods/...flash-what.html?

Obviously that is an American product, but is there something similar for the Japanese version?

I for one would be super keen on raising the rev limiter on my coupe to 7100rpm. According to my gearing and power calc estimates, we would benefit from the higher rev limit in every gear, and that is not taking to account the extra top end power which may be released with the remapped throttle.

The higher rev limiter doesn't seem to affect reliability either from what I have read.

Any thoughts or experiences?

[180 wanabe]

what is the stock rev limiter? on say a 03 coupe? mine seems to rev out to 7000 just fine even though the red line is 6500

[scathing]

what is the stock rev limiter? on say a 03 coupe? mine seems to rev out to 7000 just fine even though the red line is 6500

6850RPM is where the cutout is. The markings on the tacho should be for 6600RPM.

Has anyone here with an early model V35 had experience with rev limiter/ECU mods like this one:p

Yes. I am pretty sure the Technosquare product is what Pro Concept has, and my 2003 350Z has been flashed with a 7200RPM redline.

that is not taking to account the extra top end power which may be released with the remapped throttle.

You won't see much.

I had my redline bumped up to 7200RPM, replaced the lower plenum with a Motordyne MREV2, fitted TopSpeed extractors and Crawford High Flow cats (previously I had the catback, plenum spacer, Popcharger & Unichip) with the ECU retuned after all the hardware changes, and to the new cutout.

From my old 6600RPM redline to the retune to 7200RPM, with those extra breathing mods I picked up around 10rwkW total. CRD noted that after 7000RPM my power curve plateaued, and so I asked them to tune the engine conservatively. I didn't want it to try and make power up there, but just give me a few extra revs in case I needed to hold the car in a lower gear either at the end of a straight or coming out of a corner.

I suspect that the MREV2 is a modified 2003 lower plenum (since Motordyne offers a rebate to customers who exchange the stock piece from a 206kW engine with their MREV2, but won't exchange the lower plenum from a 221kW engine). Our stock ones are meant to choke the engine above 7K, and the MREV2 behaves in the same way.

The MREV2 is designed for the 221kW engine, and it seems to bolster the midrange (lost with those shorter runners) while not choking the engine to its 7000RPM cutout.

I've got mates who've fitted the 221kW lower plenums to their rebuilt engines, and the shorter runners don't come into their own until past 7000RPM.

As an aside, if you do rebuild your 206kW engine to aim for an 8000RPM redline doing a straight swap of your lower plenum for theirs might be beneficial to both sides. I haven't seen numbers to prove this, though.

The higher rev limiter doesn't seem to affect reliability either from what I have read.

I haven't had any problems, but due to the lack of power past 7000RPM I change gear at 7K anyway. I also only rev it out there on the track; on the street I still shift below 6800RPM.

The stock gudgeon pins won't tolerate any more than 7200RPM before slowly stretching (which may be why Nismo sells their own to permit a higher cutout on otherwise stock internals). They will apparently snap instantaneously at 7800RPM.

The extra revs do help. Not that it's much use to you in Melbourne, but at Wakefield there's a couple of places where the stock cutout would be tripped but the extra redline allows me to full throttle the gear. I was chasing a mate with another Z33 and I'd pull a significant gap on him in those places. They either had to back off to avoid the cutout, or change gear.

[MaXiMuS007]

Thanks for the detailed reply, Alan.

Yes. I am pretty sure the Technosquare product is what Pro Concept has, and my 2003 350Z has been flashed with a 7200RPM redline.

I don't suppose you know of anyone in Melbourne who does the reflash as well? And cost (PM if you prefer)?

I had my redline bumped up to 7200RPM, replaced the lower plenum with a Motordyne MREV2, fitted TopSpeed extractors and Crawford High Flow cats (previously I had the catback, plenum spacer, Popcharger & Unichip) with the ECU retuned after all the hardware changes, and to the new cutout.

From my old 6600RPM redline to the retune to 7200RPM, with those extra breathing mods I picked up around 10rwkW total. CRD noted that after 7000RPM my power curve plateaued, and so I asked them to tune the engine conservatively. I didn't want it to try and make power up there, but just give me a few extra revs in case I needed to hold the car in a lower gear either at the end of a straight or coming out of a corner.

Only gained 10rwkw with all those mods and the reflash? I would have expected more. It really is super hard to wring out the extra power on these engines without going for FI.

I suspect that the MREV2 is a modified 2003 lower plenum (since Motordyne offers a rebate to customers who exchange the stock piece from a 206kW engine with their MREV2, but won't exchange the lower plenum from a 221kW engine). Our stock ones are meant to choke the engine above 7K, and the MREV2 behaves in the same way.

The MREV2 is designed for the 221kW engine, and it seems to bolster the midrange (lost with those shorter runners) while not choking the engine to its 7000RPM cutout.

Yes, from what I've read the MREV2 is only for the 221kW engine. Why did you go for it instead of just a plenum spacer, like the Motordyne 5/6" or 1/2"? According to the reviews I've read, thos increase power right through the rev range including the top end and provide a 10-14hp increase on their own, not to mention keeping the intake nice and cool.

The stock gudgeon pins won't tolerate any more than 7200RPM before slowly stretching (which may be why Nismo sells their own to permit a higher cutout on otherwise stock internals). They will apparently snap instantaneously at 7800RPM.

Yes, I wouldn't be revving higher than 7200RPM on the stock gudgeons. A new set of pistons would really be in order for those sorts of speeds.

[scathing]

I don't suppose you know of anyone in Melbourne who does the reflash as well? And cost (PM if you prefer)?

Unfortunately not.

Only gained 10rwkw with all those mods and the reflash? I would have expected more. It really is super hard to wring out the extra power on these engines without going for FI.

Considering you pull around 15rwkW with just a catback and no software mods, I was expecting a bit more.

It's also really surprising considering how badly designed the stock manifolds are. I was expecting to hit 200rwkW with the mods and the tune.

For the record I went from around 183rwkW to around 195rwkW. As a note, most 350Zs baseline at 155rwkW where V35s seem to run 170rwkW in stock form. With all the bolt-ons, you guys may crack 200rwkW.

Yes, from what I've read the MREV2 is only for the 221kW engine. Why did you go for it instead of just a plenum spacer, like the Motordyne 5/6" or 1/2"?

I have both. I read that the MREV2 was meant to get some gains on the 206kW engine, but just not as great as the 221kW engine.

It wasn't until I read a bit more closely that I realised it might not be the greatest mod in the world. But since I was ordering a bunch of other stuff from the US, I figured I'd make the most of my shipping costs.

[MaXiMuS007]

Unfortunately not.

Considering you pull around 15rwkW with just a catback and no software mods, I was expecting a bit more.

It's also really surprising considering how badly designed the stock manifolds are. I was expecting to hit 200rwkW with the mods and the tune.

For the record I went from around 183rwkW to around 195rwkW. As a note, most 350Zs baseline at 155rwkW where V35s seem to run 170rwkW in stock form. With all the bolt-ons, you guys may crack 200rwkW.

I have both. I read that the MREV2 was meant to get some gains on the 206kW engine, but just not as great as the 221kW engine.

It wasn't until I read a bit more closely that I realised it might not be the greatest mod in the world. But since I was ordering a bunch of other stuff from the US, I figured I'd make the most of my shipping costs.

I've seen your dyno graph on the 350z forums - 195 is still a decent output. It must pull considerably harder.

I note there's been a little bit of talk about the Osiris flash upgrades http://secure.uprev.com/osiris-engine-mana...osiris-standard. They look great, but I don't think anyone has any experience locally. It looks like a great option, even if just to raise the rev limiter, remove the speed limiter and fix the throttle.

By the looks of it a decent exhaust and a plenum spacer probably give the best bang for buck for bolt ons...

[scathing]

A decent catback and ECU tune is the best, in my opinion.

The ECU tune increases power across pretty much the entire rev range, so even though it doesn't make that much outright power it still makes the car feel a lot better.

I found the stock, mild steel manifolds and cats, with a stainless catback gave the best exhaust note as well.

[Stephen Thorpe]

A decent catback and ECU tune is the best, in my opinion.

The ECU tune increases power across pretty much the entire rev range, so even though it doesn't make that much outright power it still makes the car feel a lot better.

I found the stock, mild steel manifolds and cats, with a stainless catback gave the best exhaust note as well.

What size piping and type of muffler?

[scathing]

What size piping and type of muffler?

My catback a HiTech one. 2.5" piping all the way through. It has a Y pipe that joins into a single mid muffler. That mid muffler has a single exit, which then curves into the rear muffler. 2 exits from that, with OEM-sized tips.

So it goes from a pair of 2.5" pipes into a single one. Then 2 tips at the end.

All the pieces in the exhaust are visible in this pic.

Most people in Australia and the US I've talked to agree that 2.5" with a single midpipe is the best exhaust design for a stock engined NA FM platform car. A 2.5" true dual loses a noticeable amount of midrange for about a 1-2rwkW peak power gain (i.e. dyno measurement error), which not even a cross pipe completely fixes.

3" is a bit too big - the APS TT with a true dual 2.5" catback that provides a very good power curve while still being ADR legal....and making 280rwkW.

[MaXiMuS007]

Raising this from the dead...

Does anyone know a place in Melbourne which can reflash the stock V35 ECU? I would like to be set up properly for my next track day.