I've talked about this setup for years and thought I'd finally post some pics. The setup is 225/50R15 BFG drag radials mounted on 11lb Mazda Millenia 15X7 rims. The combo weighs in around 36lbs. The tires are 23.5" tall or about 2.8" shorter than the OEM setup. The shorter tire gives an effective rear gear ratio of approximately 3.67. I ran this combo at the strip my first time at the strip back in May 2005. On the same day at the strip, I ran both the OEM 17s and the DRs. The DRs actually slowed me down fractionally and sucked out about 1.5mph (14.49@97.6 vs 14.51@95.9). I blame the reduced performance on the forced shift in 4th rather than holding 3rd the whole run. My 1/8 mile times were about .1 better, but that 4th gear shift killed it.

However, that was back in May 2005 when I was stock. My mods now include a spacer, Revup airbox, HR-y-pipe, and 20lb lighter midpipe. I also know a lot more about the car now than I did back them. It's time to bring them out of retirement. I also plan on getting the Technosquare ECU which will increase the rev limiter to 7100rpms and allow me to hold the gears a bit longer. I don't know what will happen when I head back out to the track in early November, but I'll keep you guys posted.

 

better bump it to 7200 and shift at exact right time all the way down the track... because if the ratio is what you say it is, you are going to barely make it through the 1/4 in 3rd (with precise shifts).

That's why I added rod bolts, springs and oil pump when I had cams installed - so I could bump it to 7500 for little wiggle room... 7200 barely makes it.

 

Yep, I'll probably be hitting the limiter just short of the finish (50' or so is my guess). I won't be getting the TS ECU before I go out to the strip in November so we'll have to see how the short tires play out with the 6600rpm limiter. Having the rod bolts and oil pump adds a good margin of safety on these VQ35s. Even revving to 6900rpms makes me a little worried. The VQ35 is no where near as smooth as the VQ30 at 5000rpms+. Big V8 pistons will do that I suppose.

 

I have made 150+ passes using a 7100 redline.......my car also now has 92.6k miles on it. You will be fine. I run a drag radial that is 1" shorter than stock 45 series 18's. The difference something like 3.5% shorter.......I would imagine the diff b/w your two is pretty staggering.

 

you should be fine to 7200... TS did some testing years ago and determined thats the cut-off safe range for the DE.

 

What oil pump, rod bolts and springs did you upgrade to OCG35?

I've heard that 7200 is safe. I know that the redline is 6600, but the limiter is at 6800.

 

OEM RevUp oil pump and bolts... they are a little heartier and should sustain 7500 on occasion (much more so than the DE bolts, which are a known weak point)... JWT springs

 

7200 rpm will be fine, as long as you're not running a 5AT -- do not raise redline unless you're on a 6MT. I ran mine at 7500 for a while without issues but eventually backed it down to 7000. Power drops off steeply past 6500 without headwork.

 

where do you get this idea??? They have the same engine... I'm AT and ran 7200 for a long time (drag many times at that rev limit)... and since have bumped to 7500 (with mods mentioned earlier)...

Can you explain why you feel AT cant run to 7200...

BTW, the reason for bumping rev limiter isnt for added power... the thread is about AT making in through 1/4 mile in 3rd gear with shorter gears (or in DaveBs case, the equivalent with smaller rear wheels).

 

It's not about the engine, it's about the transmission. A shop supposedly toasted a boosted 5AT due to raising the redline. If I'm wrong, feel free to share your opinion -- I'm open to correction. I'm just giving my '02.

 

^^^ got more info? link or what shop?... I ran 7200 for along time as have many others. I dont see any reason it would damage an AT.

BTW, I'm not talking about extended durations of 7200... but with an MT you shouldn't stay in that range for extended periods either.

This thread is about bumping rev limit in order to stay in 3rd without losing speed by shifting to 4th in 1/4 mile... 7200rmp is very breif period.

Still, I don't understand why you insist AT shouldnt do it.

 

It may be different it you are BOOSTED, but NA raising the redline to 7200 should be completely safe.

My car made power all the way to redline on the dyno, unlike typically seen dropoffs at 6400. I wonder where it would start to fall.