3.4 DOHC vs. 3500

[Scott_68B]

I'm posting this question in the DOHC section because I'm interested in what the DOHC guys have to say. Sorry if this has been asked before but I didn't find anything in a search. Lately, I've been intrigued with DOHC motors, mostly the 3.6 VVT. But I'm wondering about the viability of the 3.4 DOHC. It seems to me that the 3500 is putting out about the same amount of power as the 3.4 but has much more aftermarket support. What do you guys think, why should I even consider the 3.4 DOHC over the 3500?

Thanks for any opinions you might have. I'm not trying to start any arguments here, just looking for some different view points.

-- Scott

[dohcfiend]

it's all a matter of preference. if you can, get access to both cars equipped with both engines and decide.

the only situation where i would declare a clear bias towards the lq1 is if you are putting it into a 5 spd fiero. 3.4 dohc hands down.

[z34phoenix]

i am just partial to my DOHC. but the smart move would prob be the 3500 mainly cause the aftermarket and chance of future support where as the DOHC is only going to loose the little support it has... with little to no chance of any further aftermarket.

but the DOHC is a high rpm screamer. and the sound of the engine ...its just great.

[SappySE107]

Weight, Fuel economy, cheaper to modify and maintain. These are the reasons I am switching from the 3.4 DOHC to the 3500. With a cam and tuning, you can spin the 3500 to 7000. Its not going to sound the same but you can pull some RPM. Either motor will need solid lifters if you want to push it much past that though.

If I was building something to race, the 3.4 DOHC and a large budget would be the way to go. Or 3.6 DOHC...then its no contest any way you look at it:P

[Scott_68B]

Thanks for the feedback everyone, it confirms what I was thinking. Anyway you look at it though, the 3.4 DOHC is a very interesting motor.

-- Scott

[95Grand-Am]

Is there a big weight differance between the 3.4 DOHC motor and the 3500? They should be close shouldn't they?

[SappySE107]

The DOHC has a lot more weight on top, which is not good for handling. The 3500 crank is heavier than the DOHC crank but its also steel vs iron. It may be within 100 pounds, but the 3500 has to be lighter. less valves, less springs, less cams, less cam carriers, less intake manifold weight, and the block is 5 pounds lighter (3400 vs 3.4 DOHC).

Infinite adjustability in the cams and far superior head flow are the 2 keys to the LQ1. I don't hate the motor by any means, but I wouldn't use it unless I was comfortable with working on it and had room to deal with the timing belt.

[gpse3400]

The 3500 even the 3400/3100 as far as I can see superceeds the TDC in replacement parts and cost of modification. Not to mention the fortified bottom end. The lighter weight is somthing that is readily seen when you do make a swap from a TDC to a pushrod. Also the TDC is kinda tempermental to weather changes. One day moving well, another day mediocre. The benefit of it being stock is that it does run on regular fuel. So does the 3500. Oh and a 4T60-E not a transmission it appreicates as the gearing ment for engines with a broader power band. Changing the final drive helps but the 2nd gear spread is really too wide for it. I have always prefered the pushrod engine for it's simplicty, repairability and fuel economy. And hehehehe I enjoy the Rock Crushing Sounds of the pushrods and rocker arms, plus the the GEN3s arent raspy sounding at all.

My TDC is running fine right now. Did some tuning I was able to coax some extra power and fuel economy out of it. I dont love it, but I know it loves me as I'm the only person on Long Island that gives a damn and can fix it correctly...I have had the alternator fail at the Holland tunnel.. that is not an experiance I will forget. Repairbility of critical parts on the fly is not going to happen with that engine....And if you need a shop to fix it, forget it. More than what the car is usally worth...which ain't that much already...

We are all in this together. Pick whatever you like.

[Superdave]

my 3500 sounds insane at 7K RPM

http://www.v6z24.com/gallery/shows/v6z24/2007v6bash/video/2007+V6+Bash+-+Dave+Dyno.mpg.html

[gpse3400]

I belive it as I can see in your vid.. My old 3400 ran as high. Didnt make as much power as you but it had some bottom end and fuel economy to talk about..... Wish I built it diffently..You live and learn.

Here's mine on the dyno from a couple of years ago

http://60degreev6.com/forum/gallery/misc.php?do=downloadfile&i=321

[pwmin]

hey, what's with all the pushrod love in the DOHC section? lol


I drove an IMPY 3500 (a little too heavy to compare) and a G6 3900 6-speed and stock-for-stock, i would actually have taken my LQ1. It just feels and sounds better to me.

[gpse3400]

yeah I gues we kinda hijacked that one OOPSY

The new impalas are heavy at 3600lbs. Compared to the early Wbodies that a bunch heavier. Even G6s are at 3500 lbs. the new Malibu is like 36-3700. Oddly enough my monte is at just below 3500...go figure...