Most out of V6 NA?

[NCamiolo]

Simple question:

What can I do to get the most out of my 6g72 without forced induction. I'd Like to make something fun to drive without a turbo. I'm basically looking for a list of things I would need to squeeze out the most HP hiding in my engine.

Thanks,
Nick

[mrg7243]

I don't remember the official but its the highest for an na is by a 3.9 6g7x hybrid motor. But there are several things you can do, 6g75 intake manifold, Rpw cams, headers, and depending on how far you want to go an engine swap with cams or a build. If I may suggest check out galanttuner.com to see the record holder and get higher on depth support over there for the v6

[foxbrand]

damn MRG, you read my mind and I had something that I was already written out, well here it goes anyway

are you sure you want to stick with the 3 liter? switching to a 6g74 and 6g75 (3.5 liters and 3.8 liters respectively) have way more power easily (especially the 6g75) than the 6g72 out of the box and dollar for dollar will provide more power

first off, search button
second off, if you truely want to stay with the 6g72, I have a few questions of my own for you

how much do you want to spend?
how much power are you looking to get?
how much time are you willing to invest in this?

ok, first few easy ways of getting more power goes as follows, it is in order of difficulty, also it covers supporting mods

cold air intake

6g75 intake manifold, a 6g74 intake manifold can be used but it isn't as high performing, with the 75 IM, it is required to fabricate mounts for the throttle body cable, the 74 IM on the other hand drops in

a smaller battery and/or relocating the battery behind the left headlight or to the trunk, this will previde more clearance for the bigger intake manifold

thermal intake manifold spacer and throttle body spacer

free flowing exhaust and high flow cat

wideband o2 sensor, taxtrics cable and tune ($65 stage 1 tune from Blackheart motors, tune is not on a dyno but is with the car on the road)

RIPP mods long tube headers (OBX or RPW headers will do fine) but they are going out of production or if you can get ahold of boostzealot he as a set of light weight long tube headers he made that are basically the same thing

6g74 or 3000gt VR4 fuel rails and adjustable fuel pressure regulator


the next few mods are more difficult and expensive than any singular mod previously listed as well as none are truely adding more power to the crankshaft

5 speed swap, transmission can be sourced from a 3g Eclipse gt
>while your at it, get ahold of a lightweight fly wheel
>a stage 0 or stage 1 clutch
> if you have the money, throw in a limited slip differential too

solid engine mounts, this won't give you any more power but will prevent the engine and transmission from moving around

ok, these are the heavy duty mods, sans the headers, the mods previous can be applied to a 6g74 and 6g75 engine, the following is in no particular order and are very very expensive

the engine block will need maching one way or another, so also get it hot tanked

high compression forged pistons with bore over, Mahle powerpack pistons are some of the lightest on th market and are both friction and thermal ceramic coated
or a Brian Crower 84 mm stocker kit, with 93.5 mm bore pistons, engine will displace 3.4 liters, this is $5250 before shipping and tax

ported 6g75 heads, these are not neccacarily needed, but you need high compression pistons as these heads will drop you compression ratio to begin with, BUT these heads are immensly high flowing (somewhere along the lines of more flow than LS7 heads)

walbro, aeromotive, etc high flow fuel pump

bigger injectors

ARP main stubs

ARP head studs

ACL main and rod bearings

ARP connecting rod bolts, if not provided

high performance head gaskets

RPW cams

high performance valve springs

adjustable cam gears

custom Xcess intake manifold
or if you have the money and not require emmission testing, individual throttle bodies will provide even more flow but will require a stand alone computer and a speed density sensor to operate

at this point you will need another tune to maximize perfomance

->except for the pistons and stroker kit, all of this can be carried over to a 6g74 or a 6g75 (which you don't have to switch cylinder heads, also with this engine you need thicker connecting rods like from a 6g74 or custom forged rods), for these engines, custom forged pistons are required


=> building an naturally asperated engine is different than building a turbo engine, 'it is a science in itself' mysticj, so not one singular mod will provide a huge boost in power (though I am partial to that stroker kit), the heads and headers for example, can be tuned (ie primary length) to work the best with the cylinder heads to provide the best scavanging with a specific cam profile, the same goes with the intake tract

[NCamiolo]

Ok well reading that has left me another question:

How easy is the engine swap? I'm looking to get the most for $3-4k over the next year or so.

[foxbrand]

my previos post wasn't meant to scare you, seriously that is basically what you need to max out the 6g72 n/a

that will easily cover an engine swap with a 5 speed trans and a high performance clutch along with some other goodies (you have to get an ecu reflashed to run a bigger engine), I've seen 6g74's go for around $200 on carpart.com, 6g75's will cost more than three time that

as for how easy a swap, I'm not one to say from experence, but as is frequintly mentioned in the swap threads, it will take between a day (if you get help from somebody reallly experenced) to a couple weekends, depends on your learing curve, though if your going to swap the motor, for whichever one you choose get the compression checked out (also pull the heads and check for damage to the valves and piston crowns), change the head gaskets+head studs and change the timing belt+tensioner+water pump, if you have the engine on a cart, I would do that since the engine is not in your car yet and everything is really accesable

edit: forgot this, to use a 6g75, the 6g74 fuel rails, which require the use of a 6g75 lower intake manifold, the distributor from a 6g72 or 6g74 with a spacer plate

4 grand will probably cover all of it

[NCamiolo]

Hmm, so it looks like I'd need to find someone around South Jersey that would be willing to help me locate and store parts, then help with the swap when everything is ready.....I'm honestly borderline going back to a V8 vehicle at this point.....I think the biggest discouragement is my body work right now.

I miss my H2!!!

[foxbrand]

don't be discouraged, a few guys here that have done this swap will probably post up soon and tell you about it, look up Beam514's build thread, he did the swap solo (and wrote the tutorial on here), also a big powerful engine in a beaten up car is always priceless and unexpected by everyone else

use car-part.com to locate engines and transmissions, you'd be surprise on what you can find there

[NCamiolo]

I've already been on it, but it still leaves me with the lack of know-how and tools, I wanna dive into it myself but I'll need to find someone else that knows what they are doing.

Actually I need a good body shop person that wants work on the side and will allow me to help, then I can clean up my horrible looking rear quarter panel!

[G-code88]

Just be patient and in the end it will all be worth it

[M-Rod]

Overall cost should be pretty easy to map out on my garage page. For starters, your best bang for the buck would most likely be the manual transmission swap. When you become more familiar with the details of the 6g7x engines, the 6g75 swap becomes very easy. There is easily enough information floating around various locations online. Search and don't be afraid to ask questions along the way.

[M-Rod]

edit: forgot this, to use a 6g75, the 6g74 fuel rails, which require the use of a 6g75 lower intake manifold, the distributor from a 6g72 or 6g74 with a spacer plate

Are you sure? And how do you exactly know this?

The 6g74 LIM must be used on the 6g75 if you plan to use the 6g74's fuel rail. How do I know this? From actually doing the swap.

Also, the distributor does not need a spacer. How do I know this? Once again, from actually doing the swap.

I may be coming off a bit harsh here, but seriously, don't spread incorrect information just because you think you know something until you've actually done it. These kinds of things just get frustrating when time and time again somebody will come along spreading wrong info based on what they hear or think, and haven't actually done.

[SPD_FRK]

Save your money...


Don't even mess around with the stock 3.0L engine. That is outdated and honestly will be a severe disappointment and waste of time modifying for this platform.

If you want anything remotely like V8 power potential then you will want nothing short of the 3.8L 6g75 engine swap. Doing the 5-spd manual transmission swap will be a great improvement, and even with the stock engine as you will be able to free up more power to the wheels and drop a substantial amount of weight.

The 5-spd swaps average anywhere from $500-$1500 depending on how much you have to pay for all of the parts.

Depending on the condition of the engine you find you may not spend very much, just changing gaskets and timing belt components will be roughly $300-$500 depending on what gaskets you will change out.


Modifying the engine is where you will spend a bit more money to make power. Currently our own 6g75 build has pushed close to $3500 on strictly the engine alone, and we still have our cams and fuel system components to add into the costs.

[foxbrand]

Are you sure? And how do you exactly know this?

The 6g74 LIM must be used on the 6g75 if you plan to use the 6g74's fuel rail. How do I know this? From actually doing the swap.

Also, the distributor does not need a spacer. How do I know this? Once again, from actually doing the swap.

I may be coming off a bit harsh here, but seriously, don't spread incorrect information just because you think you know something until you've actually done it. These kinds of things just get frustrating when time and time again somebody will come along spreading wrong info based on what they hear or think, and haven't actually done.

yeah, I'm going to be off for awhile as my school load is really getting in the way lately
I was listing that stuff as reccomended, and unfornantly the LIM that I listed there was a typo, right, I meant 67g4, my bad

I was about to post the tutorial for the swaps right now and edit that information out, but thanks for coming in