I was lucky enough to buy my car with stillen headers already installed. However, if I had do the install with the car I would just do the PPE long-tube headers since they have better gains. They wouldn't work with your current Berk HFCs though :-\

 

PPE headers are very nice, but also very pricy! Plus I would have to get them customized to be legal in STU, so even pricier-er.

 

They look nice! What are your initial thoughts? I'm going to be pulling the trigger on HFCs very soon, just not sure what direction I want to go (Berk, Z1, Fast Intentions???).

Right now my heart wants it to be warm out so we can get this season started!

 

When I had talked to concept Z when I pulled the trigger on getting my HFC's, I had asked for their opion on which ones were the best. They said that they were all about the same. Ended up just buying the kinetix. For the money they seem great and look just like most of the aftermarket cats on the market. Best of all no CEL and doesn't need a o2 sensor standoff like most on the market.

 

I'm getting some serious cabin fever! So desperate that I was happy that the groundhog didn't see his shadow.

I picked Berks because I got a killer deal and they have a decent reputation. I haven't started the car since December, still missing the new Y-pipe. I heard the Z1 HFC are ok too. RT Tuning recommended Stillen.

 

My intentions for 2015 were to improve/modify the suspension and differential. Largely set by the time I had to work on the car before the first event and the budget I set (and went over by 30%). However, I couldn’t bring myself to bolt the stock exhaust back in. At least not the muffler.

I considered a couple choices like: AAM, Megan, Tanabe.

Considering weight and price, the Tomei Ti Full Titanium was the best choice. Not a fan of the boy racer blue tip color, but ok.

I did get warned for being too loud at an event (96db) and that was with stock headers, cats, and y-pipe. I’ll have to order a downturn this year and hope for the best.

 

I just bought a base 2007 350Z to prep for STU this year after selling the E36 M3 I had been running in STU the past few years. I found a good deal on a used Tomei titanium so it's the first part I put on the car. With everything else stock (y-pipe, cats, headers) it's LOUD! I haven't driven it with the silencer in yet but I suspect I'm going to have to do a turn down or other solution.

I've heard Z1 modifies the silencer to meet sound at AMP (95db), might be worth a call to them to see what they do.

 

I'll have to contact Z1 to see what they do.

One thing I forgot to mention, I built a skid plate for the Tomei muffler out of aluminum.

The car was initially sitting very low. About 3.5in of the ground. I hit a couple big bumps that tore the lower expansion spring completely off. It also put a dent in the lower front part of the muffler with a shower of sparks.

 

From the looks of mine the previous owner already took care of that for me

 

Im in the process of redesigning my whole exhaust with a custom setup and selling my Tomei. If you need a turn down I can sell you the one I was using. It worked for Nats last year. I have set screw holes so you can angle down or away from the sound meter or have options for using steel wool if u need it. The Tomei is crazy loud in just about any configuration(110-120db measured at several events in STU trim)

 

I have a strong desire for the Tomei. But the DB level is just too much. My local non-SCCA club probably wouldn't care unless someone started complaining. But I want to be able to confidently run at Devens without worrying about it.

How much does a turn down help? We talking 110db turning into 95db? Or 110db turning into 105db?

 

I raced at Devens with this exhaust a few times last year. I probably have talked to you before lol. I had to use steel wool and the silencer to make it pass. I have a Nismo S tune I run at devens most of the time and even that needs screens with steel wool to pass there. That place is fun but with 90db requirements its annoying. You basically need a stock exhaust. The Tomei will run at 110db open. Silencer is good enough to pass at any national event 95-97db but robs power. The turn down setup is best to keep the power up

 

thanks for the info (again..). I wish there was a good consolidation of exhaust DB levels for autocross purposes. Not exactly cheap to test them all out.

sorry for the hijack, hajwoj. Please carry on.

 

No problem. Thankfully there are no Pro or Tour events at Devens this year so I don't have to worry about it. I did 22 events and only one warned me about sound. And that was only because of a person from a local neighborhood coming over and complaining about a heat I didn't even run in.

 

Last year I had no plans to do anything to the engine, ie Tune, intake or exhaust. However, 5 autox in and the stock rev limiter had to go. This was the last event with the stock rev limiter. Going downhill into a righthand sweeper. I upshifted to 3rd and lost time, but sat on the rev limiter and gave up time. Currently have the rev limiters 6800 and 7000. May set one more to 7200, for those times when a win is more important then my engine life The car also still had large understeer, but I'll get to that.

 

Speaking of rev limits. Last year I ran RS3 v2 285/35-18. I bought these mainly because I got a good deal in late 2014 and I wasn’t in the Autox sawing-circle yet to know about the RE71R. I had good success with the RS3 all season, and after 122 runs, they are showing some wear. I did fight the temptation to buy the RE71R all season long, but my car was half done and I wasn't doing any national events.

2016: So the 285/30-18 RE71R are coming out soon. If they were 35 size, all would be good, and I could find some other things to worry about. But being 30, they will limit my top speed. Here is a quick and rough comparison.





I thought about going to a 19in wheel in the rear
Some pro’s: higher top speed, potentially longer time in the higher torque band (depending on course)
Some con’s: heavier, slower acceleration, can’t rotate tires front to back.

Plus the 19in tires are 35 tire wall? Which really screws up the front to back size ratios. Stock is 3% difference.

5% 275-18 to 285-19 comparison
8% 285 size 18-19 comparison

I think the cars computer won't know how to deal with these size differences.

Anyone considered this and want to validate my genius, or confirm my stupidity for considering so many cons?

 

Are you sure your gearing numbers are correct? Our data says we top out at about 61mph on our 6900rpm limiter with 285 RS-3s. Your chart shows 67mph which is a big difference.

I don't know about the size difference front to back by using 19" rear wheels. Is the ABS affected as well, or is it just VDC that goes crazy if there's too much diameter stagger front to rear?

The car looks and sounds really good!

 

Thanks Bryan! The 67mph is for the 19inch wheels (middle table).

Looks like the data you collected is close to the table showing the 275/35-18. All the tables in the previous post are for the RE71R tires, and 350Z published gearing. I couldn't find any reliable tire diameters for the RS3.

I don't know if only the VDC is affected or ABS as well, hoping someone who tried would share their experience.

 

The two systems are linked in some way I'm sure, I'm just curious for Base model cars with no VDC to be honest. I've heard VDC can be finicky with large differences in tire diameters. I forget what it does other than throw a light.

Oops, reading comprehension fail on my part there with the chart. Still, I don't think we've seen over 61mph (SoloStorm GPS) on any tire, and the 285 RS-3 feels a little taller than the 275 RE71R.

Another thing to consider is 19" rears will add rake, so adjust ride heights accordingly if you find it oversteers too much. I've thought about it myself but have been too cheap to take the plunge.

 

Do a quick search for " ice mode" is what it's called. Base cars have had this problem too.

I've had it with a staggered ( in proper height) combo and square combo's. I also think race camber settings assist with bringing it on.