How much HP can the 4.0 hold up to?

Rickmaan1

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May 18, 2005
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Just daydreaming about power adders that I most likely won't ever have the money to buy, but it got me wondering about how much the stock 4.0 will handle before things starts breaking?

With a supercharger, ported heads, custom cams, long tube headers, and a good tune, it looks entirely possible to top 400 fwhp with basically bolt on mods. According to the SSM website, head gasket retention and the hyper pistons can become issues with only adding mild boost, making the rest of the potential bolt-on HP a seemingly pointless exercise.

As I said, just daydreaming here, not seriously planning anything as costly as a supercharger right now but I like to hope at some point (maybe in 2 years when my factory warranty expires) I'll be tweaking my V6 for a good jump in HP so I was just curious if anyone knows just how much you can do to a stock V6 before something gives up, and usually what it the 1st thing to go?
 
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OK, since nobody has responded with any info yet, how about this;
What mods have you done to your V6 to increase power, and have you experienced any issues because of those mods?
 
It is slow here for sure. I don' think i've been here in 2 years.

I have a2005 V6, Vortech supercharged, intercooled, gt500 heat exchanger, MAC LT's, off road pipes, Prochamber, Zabtech throttle body, 3:73 gears. There is more, but for this discussion I just put the motor mods.

I run 12:62 in the 1/4, and have run 11:75 with the addition of a 75 shot NOS. As with others who did the dual power adder, the motor let go.

I also ran 13:81 with just bolt on's. (just a little background)

The general thought is about 360hp at the crank will keep things running smoothly. There are folks putting out over 400 with the 4.0, but they usually do not last long. I have never dynoed my car to see so I don't have a chart to show. 330 rwhp makes a great ride.

There is one powerhouse turbo car that gor into the 11's on boost alone that is privately owned, the rest had dual power adders.

I have just installed a 2.62 pulley and an adjustable BOV to get up to 14psi (I only had 9 before). I will soon get to the track to see what it runs.


The quickest privately owned 4.0 ran a high 10.90, PHP ran 10:88 with a pure race car 4.0 dual power adders.

My car-


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Thanks, that's the kind of info I was hoping to see. Just for curiosity sake, when you put in the 3.73 gears did you put those in the stock 7.5 rear or did you swap out the rear for an 8.8?
 
I have the 7.5 because I have invested a lot into it, were I do it it from scratch I would have an 8.8. I have purchased 2 t-locks, 3 sets of gears, an auburn dif and a T/A girdle plus fluids, plus 7.5 specific tools.

In the car right now is a 7.5 t-loc with 3:73's, which I know will not hold up (the spider gears go first) I will be reinstalling the 7.5 with 4:10's, auburn diff, T/A girdle and 3" studs.
 
I've just picked up a 2007 V6 convertible that has 3,500 miles, all stock and MINT. What does everyone recommend in order to get some extra boost from this engine and still keep within a $2,000 budget?

Thanks,
Jim
 
A tune and rear end gears, best bang for the buck on the V6. Dual exhaust will change the sound, but not really add much HP. Cold air intakes are popular, but are worthless without a tune and even with a tune don't add more than 10-12 hp. With the stock long block there just doesn't seem to be the easily made HP with simple bolt ons like the 4.6 gets. Rear gears and supercharging have been the only things I've read about that make a dramatic difference in how the V6 car performs. With a $2000 budget, you could get the stage 2 ported heads from Super Six, but if you have to pay for installation that won't leave any budget left for anything else. The heads by themselves will make a noticeable increase (if you can believe the dyno charts on the SSM website), but it's a high $$ to hp ratio, almost $100 for each HP increase. However, IMO they would pave the way for better increases from other add ons like the exhaust and CAI.
 
A tune, intake, 3:73 gears w/T-Loc, plus a GT takeoff muffler will really wake it up, LCA's would come after that. I ran 13.81 with bolt ons, so the power is there. The above will really be felt when driving, get a package deal for the tuner and intake, and I bet you can get a deal on the other parts with your connections.
 
I've been considering a cold air intake and a dual exhaust for starters. I was not thinking about heads, but I have been curious about a supercharger. With a cold air intake, dual exhaust and supercharger (possibly heads), what kind of horsepower will I be looking at? I'm figuring it will be in excess of 300HP. Is that a fair estimate? Also, from what I have seen from the vendors, I would be looking at $5,000 assuming I do the work myself. I think I'm well into GT territory, but with something much more interesting. What do you think?
 
I installed the WMS High Velocity Intake and I'm very happy with the results, noticeable HP gain and torque too.
Best of all it has evened out the power band, there is now a smooth curve up, no plateauing around 4000 rpm. as before. Next on the list is a SCT Tuner with some custom tunes for the V6 and 3.73s.
My goal is modest, 250HP with as much of it at the rear wheels as possible. After all this is my daily driver.
 
I've been considering a cold air intake and a dual exhaust for starters. I was not thinking about heads, but I have been curious about a supercharger. With a cold air intake, dual exhaust and supercharger (possibly heads), what kind of horsepower will I be looking at? I'm figuring it will be in excess of 300HP. Is that a fair estimate? Also, from what I have seen from the vendors, I would be looking at $5,000 assuming I do the work myself. I think I'm well into GT territory, but with something much more interesting. What do you think?


I think you are right on the money, 300hp with the canned tune, more with a dyno or email tune like I have. As mentioned I have the vortech, I know a bunch that have the xcharger, known a few with the procharger, all are great systems, the x has an intercooler now and they are getting pretty quick.
 
I have a 2009 mustang v6 all i have right now is a k nn cold air intake true dual off road x pipes with roush extreme axle backs my next mod is throttle body and gear ratio 4:10 and carbon fiber drive shaft with a bama tune.
 
Speaking of superchargers. Would anyone know of where a guy could get his hands on the pulley bracket from an x-charger setup?
I have an Eaton m90 I'm putting on my v6 and need that bracket. It doesn't come with the kit I'm buying. Any help would be appreciated.