NA 3.5L discussion

[xwire]

Originally Posted by TUFFTR

My question is this OK
To get 3000GT Headers (S/S) brought over from the US Inc postage is about $600AU, which is ok.
Ive been qouted $1000AU for custom extractors for this engine.
Which means, if i buy them from the US and get them shipped over i should have a $400 clearance to get them modified.

What i need to know is, what EXACTLY needs to be modified in the 3L DOHC headers in order for them to fit a 3.5L? is it alot of work? Will it be more then $400 of work is my main one...

please get back to me ASAP!

you will need to extend all 6 pipes to make them fit correctly, the 6G74 is taller and the oil pan is slightly deeper so they do not fit, you will also need to extend he pipe that goes between the front and rear bank

I would recommend a good down pipe and use the 3.5 liters exhaust manifolds, it looses a lot of low end with headers and get noise as all hell, and with a down pipe the modifications that are required are a lot less

[StealthPanda]

Originally Posted by xwire

you will need to extend all 6 pipes to make them fit correctly, the 6G74 is taller and the oil pan is slightly deeper so they do not fit, you will also need to extend he pipe that goes between the front and rear bank

I would recommend a good down pipe and use the 3.5 liters exhaust manifolds, it looses a lot of low end with headers and get noise as all hell, and with a down pipe the modifications that are required are a lot less

Ah, i was unaware of the oil pan interfering, all good though knowledge for the future, and yeas after reading his post and thinking about it, a dp would be tho most economical/most effecient outcome..

[TUFFTR]

Originally Posted by xwire

you will need to extend all 6 pipes to make them fit correctly, the 6G74 is taller and the oil pan is slightly deeper so they do not fit, you will also need to extend he pipe that goes between the front and rear bank

I would recommend a good down pipe and use the 3.5 liters exhaust manifolds, it looses a lot of low end with headers and get noise as all hell, and with a down pipe the modifications that are required are a lot less

Awesome...
When you say downpipe, do you mean to retain the factory exhaust manifolds, and just get a nice flowng downpipe made up? Like that pictured a few posts above?
Thing is i dont have any factory headers (Didnt come with the engine) So i thought, eh, not gonna bother with factory stuff and just get aftermarket.

If the 6 pipes need to be lengthened.....i'll ring around to see how much that would cost...
Wish i could find some some extractors that still have to bolt to a downpipe of some sort would make this easier...

[xwire]

yes the factory 3.5 exhaust manifolds are not to bad of units, a little port matching and they will handle pretty much you can throw at them

yes a bolt on down pipe would be a lot easier to work with, and would not take much to adapt from the 6G72

[whitedragon]

Lotta 3.5's poppin' up all over the place!

[TUFFTR]

Originally Posted by xwire

yes the factory 3.5 exhaust manifolds are not to bad of units, a little port matching and they will handle pretty much you can throw at them

yes a bolt on down pipe would be a lot easier to work with, and would not take much to adapt from the 6G72

Thanks man.
I would prefer to get extractors though, Cause i know one day i'll eventually get them so i mightaswell do it once now.
I'll inquire a bit about the "lengthening" of the stainless pipes as i reckon this might be my best option to get S/S Extractors for it.

Thanks for the replys again

[3startuna]

Originally Posted by 3g3000gt

I guess you don't quite understand the topic. Yes I know it's hard with out the jspec 3.5L. I have found many sources to get one. I don't care for nos because I'm looking for DD reliability with more power than the 72 at all times. If I were gonna go forced fed I would TT it. NOS has been discussed in depth on this forum, I'm trying to find a more ways for us NA guys to get these 225-250whp aspirations that we have without TT conversion.

So back to the topic... What do you guys think can be reached NA with it? Or should I take the topic elsewhere. I really believe that for those of us who want a quicker NA car this would be a fairly cheap way to go about it if you can work on your own car or not.

I read that the 3.5L can be tuned with an afc and reach 190kw which is about 255hp at the crank, translating to 205whp on another forum. I see guys spending a lot of money on NA mods, when swap/sell 72/afc is cheaper and yields more power. Lets start brain storming. We have a guy on FL3S that can make the need accessory bracket as long as you get the right jspec engine so this will be an easy swap.

we can make 300whp from our NA 3.0L engines, its just not been done yet.

all we need to do is head work, have a good set of cams, and also higher compression pistons like 12:1. I believe the head is the limiting factor for the 6G.

If a 4age can make 240hp from a 1.6L or a K20A can make 300 and higher from a 2.0 and 2.4L i dont see why a 3.0 cant make the same power.

The only real difference between us and them is that those heads flow like they were built by the gods of olympus.

also id consider a 3.5/3.0 frank motor. instead of a straight 3.5

[Stealthee]

Originally Posted by 3startuna

we can make 300whp from our NA 3.0L engines, its just not been done yet.

all we need to do is head work, have a good set of cams, and also higher compression pistons like 12:1. I believe the head is the limiting factor for the 6G.

If a 4age can make 240hp from a 1.6L or a K20A can make 300 and higher from a 2.0 and 2.4L i dont see why a 3.0 cant make the same power.

The only real difference between us and them is that those heads flow like they were built by the gods of olympus.

also id consider a 3.5/3.0 frank motor. instead of a straight 3.5

You are insane to think it can make 300whp. Look at sunminds completely buit SOHC. He saw 220whp, which is about 279 bhp. A DOHC with the same type build is not going to make 80 more whp, or about 368 bhp.

Its not going to happen.