6G74 help?

[dookie]

Anyone US-based have performance mods to recommend? My 3.5l is so wheezy!

I looked into headers (years ago) when I cracked a manifold, but couldn't find anything US-legal...now getting ready to do a y-pipe, might as well pull the manifolds too, right? ECU flash? Sure wish I had the 3.8...

Also, hydraulic lifter clatter seems to be common @ startup? Have any improvements to recommend? Oil thin/thick/clean/full? Aussies report some rev-to-3k-slowly-repeat ritual to free/clean a stuck valve?

 

[IncorpoRatedX]

If you want to get the best performance out of your truck you better be running premium fuel.

for the lifters; replace lifters with revised ones. for some mild power gains; K&N cone filter for a 2G Eclipse, remove the cat,

What's the problem? are you up high in elevation? I'm running 37's on my truck with stock gears and have no complaints about the level of HP.

Throw a turbo on it, the 3KGT guys used the 3.5 in their cars to increase displacement, then throw turbos on it too.

 

[off-roader]

Yup... define wheezy? i.e. what kind of performance are you looking for?

For me right at sea level running 35's on a built up rig (i.e. heavy) with an old tired 3.5L, I have no issues whatsoever merging onto a very busy I-5 (cars merging/exiting from 2 different highways on/off of I-5). My entrance to I-5 is essentially a 90* turn from a frontage road so it's not like I have a huge onramp either. Traffic on I-5 is typically moving at speeds ranging from 60-75mph depending on what vehicles are entering/exiting within a 1/2 mile before and after where I have to get on.

That said, I do sometimes use the PWR setting to keep the transmission in a lower gear longer.

 

[Toasty]

Maybe you have engine problems, performance mods won't help that much. Find a local to you who has a 3.5 Montero to match yours and see it it feels the same.

 

[1morebike]

instead of wasting money on mods why not just get the one you have rebuilt? it will be much better and more dependable then a turbo charged tired engine.

 

[SoCalMonty]

Anyone US-based have performance mods to recommend? My 3.5l is so wheezy!

I looked into headers (years ago) when I cracked a manifold, but couldn't find anything US-legal...now getting ready to do a y-pipe, might as well pull the manifolds too, right? ECU flash? Sure wish I had the 3.8...

Also, hydraulic lifter clatter seems to be common @ startup? Have any improvements to recommend? Oil thin/thick/clean/full? Aussies report some rev-to-3k-slowly-repeat ritual to free/clean a stuck valve?

What, exactly, are your goals for the truck? Most "good" modifications will either be (1) not smog legal, or (2) very expensive, especially getting a good amount of power from a normally aspirated engine.

If you don't mind swapping out your header every couple of years when you smog, you could run the old "I/H/E" combo for a few horsepower and maybe a couple lbs of tq (intake, header, exhaust). It's likely to cost you close to $900, and I'd guesstimate maybe ~15hp at peak and ~8 lbs tq. Most of the gains would be in the upper RPMs, so you'd have to wind out the tach to really feel the most of it.

Do you frequently run it to 7500 RPM? If not, I'd enjoy it as the 4,500 pound 4x4 SUV that it is and not worry about being able to keep up with vehicles that have considerably newer engines and weigh 1,500 lbs less.

 

[dookie]

So, I have a stock, high-mileage, well-cared for '01 XLS that I would not describe as at all tired (just slow from day 1!). It is the 4s, mechanical transfer case, (optional on the XLS) hybrid LSD, and I run 265/75 10-ply ATs...if that tells you anything about gearing.

What I miss is mid-range torque...say 2k-4k? I shouldn't have to go to 3rd @ 5k to maintain 75mph uphill or make a highway pass. Towing is embarrassing if it's anything but flat. The motor is just always so wound up...maybe that's partially the 4s? Mileage certainly suffers. I thought it was pretty well acknowledged that the 3.5 is a bit modest for the Gen3?

(Perhaps a bias though...I've recently spent some time at the wheel of the wife's VW TDI. Talk about grunt. 2.0l turbo-diesel 6s w/240lb-ft @ 2k. $500 ECU flash makes it 320! 45mpg hwy.) I have done headers in a couple other vehicles, and generally found it easy and worthwhile. But aftermarket support for this vehicle in the US is so paltry.

Are there in fact revised lifters for this application? I've read a lot of complaints about noise, but no other mention of this as a possible solution. Seems a bit drastic. Ditto turbo...too much solution for my modest problem.

 

[Toasty]

Ah, you're in a Gen 3. Makes sense, I was thinking you had a mid 90's Montero. Yeah those Gen 3's were sluggish until '03 when they got the 3.8L + 5:1 first gear makes them more peppy.

 

[SoCalMonty]

Unfortunately, the build philosophy of most Japanese engines is different than american counterparts in that the former tend to emphasize HP and slightly higher rev bands, while the former generally emphasize torque and have lower rev bands.

It's not a hard and fast rule, but was mainly true for the bigger brands in the 80's thru the 00's.

 

[dookie]

Ah, you're in a Gen 3. Makes sense.

So why are the earlier ones quicker? They would have had the same 4s tranny, no? Lighter? How was the DOHC output & when was it in use? I'd hope a low-revving truck V6 would be more torque oriented...my Japanese rev fix comes from the Miata and TSX. And I definitely don't like the shift program on the 4s...it bails out of 1st before you're through the intersection (unless you paste it) and then holds 2nd FOREVER.

 

[IncorpoRatedX]

Oh you've got a SOHC, that explains it.

DOHC had, well, better flowing heads, also came equipped with dual runner intake manifold, modulated by a vacuum diaphragm that basically adjusted the runner length depending on the load put on the engine. Which allowed it to really put torque in the places that needed it.

SOHC is just... well... lacking.

Revised lifters are available for the DOHC, I have them in my truck, such a peaceful idle. I think the SOHC uses the same lifters, but i do not know, you'll want to check that.

You never did answer my question about what grade fuel you run.

 

[SoCalMonty]

SOHC engines do typically have a little more TQ down lower than their DOHC counterparts, though. Not a bad thing for a truck.

Doo, I'm actually in the market for a Miata. I wouldn't call those high revving though (don't they have a 6500 rev limit stock?!). Looking for a 6-spd NB, staying N/A with ITB's on MS. Looking for 160-180 to the wheels, ultimately. Been a while since I've had a trackable car, so I'm really looking forward to it!

 

[Mudrunner]

I test drove the 01 gen 3 and I thought it was plenty Peppy. Although I was not comparing it too much quicker accelerating vehicles. Also might look and see what you can find for the Transmission, improving that might help improve the pep overall.

 

[dookie]

I'm actually in the market for a Miata. I wouldn't call those high revving though (don't they have a 6500 rev limit stock?!). Looking for a 6-spd NB, staying N/A with ITB's on MS. Looking for 160-180 to the wheels, ultimately. Been a while since I've had a trackable car, so I'm really looking forward to it!

My '99 (5s Sport) is 7k, but it's one of those cars that just seems to want to run @ 5k+ all the time (and with no rev-limiter or accessories could easily run 8). I'm bolt-ons only (IHE), SCCA roll bar, 9lb wheels...runs well enough for amateur solo 1/2. I've been contemplating FI for more power, but you and this have me reconsidering an NA build. It's a bulletproof little motor.

 

[dookie]

DOHC systems sound more complex...did they break? Why would they revert to SOHC?

My fuel is usually the cheap stuff (in the truck). Next time I'm in the mountains I'll fill w/premium...can you put a number on what sort of hp/tq change to expect?