I'm interested in the Stillen exhaust and I was wondering if I should wait to put them on so that I can install headers at the same time. I'm not sure on the date that the headers are supposed to come out. Is there any benefit from doing both at the same time. I figured that since the exhaust was being worked on might as well do both at the same time. Would te cost be the same as far as install if I had them done seperatly? Are there any reasons why I shouldn't put stillen headers on. Any comments would be appreciated.

 

I have a set of custom 1 5/8" headers and exhaust from B&B performance in Phoenix. I prototyped both systems.

Exhaust is great.

For the money, headers are not going to do much on this car. We went with multiple setups and could not get something that offered a dramatic improvement. FYI

My advise, is that even if it is Stillen, spend your money on another mod, besides headers.

 

1 5/8" exhaust.... sounds like you would lose power!!!!!

 

1/5 8 headers not exhaust

 

heh, yeah man, hes talking about the primary tube diameter, not the catback diameter

 

but jeez man, those headers look like ****! you gotta be able to get some gains out of a new set...

 

Of course it is the primary tube diameter of 1 5/8" for the headers. We tried the following setups, 1 3/4", 1 1/2" and the set I have on now.

The difference from the factory exhaust manifold (not headers) was this:

1 3/4" - hp and torque loss through the entire range.
1 1/2" - same performance as exhaust manifold.
1 5/8" - lower end torque and hp increases. Peak was a 5 hp gain and a 7 lb. torque gain.

I doubt any header setup will get 15 - 20 hp increase. I just do not see that happening.

This car was in development for what - 6 years? I think Nissan had much more time to perfect the exhaust manifold, and that is why you will most likely not see huge hp and torque increases from aftermarket headers. Just my opinion.

 

yeah the VQ is already pretty highly developed, they had designed the original back in 92 so they've already done their homework on it before it got the the 350Z. Thing that blows me away is, the VG30 in my 300ZX made 222 hp on 3 liters(74 hp/liter) while the VQ makes 287 on 3.5 liter(82 hp/liter) but the VG still had alot of potential and guys over at twinturbo.net regularly dyno over 260+/- with headers, exhaust, intake. JWT chip(86 hp/liter) whereas its starting to look like theres no extra potential out of any of these mods on a VQ motor(intake and exhaust already tested on other threads, and we know the stock ECU already retards on pump gas ) It just seems to me that the VQ being a much more modern, highly developed, design than the VG motor(which is actually just a refinement of a 25 year old motor) should have a bit more potential liter per liter. Hopefully it still young in the Z and there will be alot of good mods to come that will really bring out a bit of decent power.

 

Is that crank dyno or on the rear wheel. If an NA 300ZX put 260 on wheel, that means it has more than 300hp on crank. That makes 100hp/liter. I don't know anyone did crank dyno, though.
And I disagree with your comment on VG and VQ. From the fact Nissan is using timing chain instead belt on VQ. You can see that it is after relibility rather than pure performance. It's a compromize to use VQ instead of VG engine on a sport car like Z. I guess the need to reduce production cost overcome the others.
The purpose of timing belt instead of chain is to gain fast and higher rev. Don't you see NA Z32 has 6800 rpm redline?

 

Were the headers full length or shorty headers (leaving cats in place)? If the cats are still in place I can see a decent performance gain from full length headers. The downside to that is they wouldn't be emissions legal and you would need O2 sims so the computer wouldn't go crazy. What I would like to see is a set of tuned length headers w/ a merge collector, they would probably make a fairly substantial power increase.
As for the original question, if you want to install headers later it would most likely not cost you any more money if you did them seperately. You don't have to pull the exhaust off to do headers and vice versa so you won't save any labor costs by doing both at the same time.

 

Im not sure what point you are trying to make about timing chain enigines not able to perform as well as timing belt engines, Porsches all use timing chains besides, the VG was designed in the early 80s as a SOHC sedan engine and only refined into a high performance engine out of neccesity. If you think that timing chains cannot be revved high somebody better go tell that to everyone that has an S2000

In any case, the 260 is calculated HP, but at least 2 of them have put thier NAs down to flat 14s in the quarter, thats what the stock 300ZX TT with 300hp ran so take that for what its worth.

 

Shorty headers leaving the cats in place. AZ is an emission state, so I still need to be legal in that dept.

 

Your last post said dynoed, now rephrased to dyno then calculated.

I know moded NA Z can run 14 flat. I have one.

There is no shame that VG use to be sohc. many great engine came from that way (if it has history). Change head can change many thing.

My point is if Nissan really go after pure performance, 350Z would have a 3.5L VG with timing belt. But even a performance enthusiast like me prefer timing chain over belt. Just to avoid all the trouble to replace it every 60kmiles. And the bad consequence that once break. But racing team with no problem to take out their engine out will prefer belt, special light weight racing belt.

Don't compare apple to orange. Different cars have different design philosophy. I think it's a unavoidable trend for less and less timing belt. After all reliability is more important than a little bit of performance gain for majority of people. Timing belt may be defined as Once a Japanese trick to gain performance.

 

I am still keep my finger crossed for the nano technology belt to come out that will not only be light weight, but also last 300kmiles

 

I hear what your saying, but timing belts are DEFINITLY not used specificaly for perfomance. There is nothing trick about timing belts or higher performance about timing belts, first off they are alot cheaper than chains and are more desirable for car manufacturers because of this. Look at just about every economy 90 hp 4 banger sold today and you will see timing belts. Second, chains are stronger than belts(obviously) and more desirable on a high output motor, this is why Honda switched to a chain on their S2000. What is it exactly about a belt that you feel makes it specific to high performance applications? Its slightly less reciprocating mass than a belt but thats it

 

Less mass to move around.

I know on some engine (VG) you can buy racing belt that free up more performance but even shorter life.

Do you know why enco cars with small engine all use belt? If they designed in chain they will come with less power (up a few hp which is essential for a 2 digit hp motor).

 

Most domestic V8s use timing chains, but they do sell aftermarket performance belt drives for them as well. Supposedly belt drives offer more accurate cam timing, light weight, and are quiet. I am glad the VQ uses a chain so I don't have to worry about a timing belt letting go, and I am sure we aren't losing much performance if at all because of it.