wolfpack219

I am sure this is an old topic and I am sorry if it is, but I constantly see people supercharging the hell out of these motors (4.6L V8 3V) with out changing anything else. This has got to be a problem with the transmissions and fuel systems right? The overall question I am asking here (and Im asking all of you becuase you have all had much more experience and testing than most) is how much power can this 4.6l 3v motor handle in reliable fashion W/O changing transmissions or anything in the motor other than obviously a tune and intake. (simple bolt on's) I ask this because I am one of those guys that loves my mustang, but I want to put a supercharger on it that will not be blowing up my motor. I also don't want to make the car unreliable. Just a little more performance but w/o having to rebuild the car. Thanks for your help guys I really appreciate it

By the way it is a 2007 GT 5spd manual with about 23,000 miles on it. Runs great. All I have done is an intake and some wheels and tires.

officespace56

Many guys use 450 rwhp as the limit with stock bottom-end, but there are few who go above 500 rwhp with the stock bottom-end. It's kind of a roll of the dice.

2kanchoo

450rwhp usually is considered the max. Some out there run more with no problems, some have had a rod snap and pistons fly. Most agree the most important part is having a really good tune. If you get a good s/c from a reputable shop with a good tune and just run the stock boost levels (typically 5-7 pounds) you shouldn't have a problem. If you get a good kit it should come with the injectors and other stuff you need. I would highly suggest having the car dyno tuned immediately after install to at the very least make sure you aren't running too lean. Detonation with FI = big chance of blown motor.

wolfpack219

2kanchoo thanks for the info! It was much needed and yes the set up will be installed by a reputable shop. I wan't it done right for sure.

don_w

Clearly, there are no guarantees with any power adder. Anything can (and sometimes does) go wrong... e.g., a failed catalytic converter cost me an engine. Keeping the boost down and having a good tune are the best insurance.

But in the end, you have to be prepared to pay if you want to play.

.

tom281

There seems to be such a wide range...... 450 rwhp was the most popular number as far as the safe limit for a long time, but there are so many people running between 450 to 500 rwhp now that you have to question that number somewhat. As these guys have said, 95% of the safe limit depends on the tune; the other 5% is made up of common sense, and luck.

JonCo

+1. pay to play.

SONICBOOST

430rwhp here with gt500 pumps..dont go too crazy with the numbers, get a solid setup with a good tune and you will be fine on the stock engine..

don_w

You know, I've thought about this whole concept quite a bit. It strikes me as odd that so many people try to quantify the limits of a stock engine (or any engine for that matter) in terms of peak rwhp. Peak rwhp only occurs at one specific rpm level (such as 6500) in one specific gear (4th). And from what I've seen, the vast majority of engine failures do not occur while the engine is running at 6500rpm in 4th gear. Often, they fail at much lower rpm levels due to detonation, or a variety of other causes. But rarely (if ever) at peak power. In fact, my stock engine windowed when a cat failed, and it was only at about 4000rpm at the time, and making under 400rwhp, with only about 12* of timing in it.

So, why do we try to say 450 rwhp or 500 rwhp or any other number is the "safe" limit for an engine? When in fact, there is no direct correlation between the peak hp number and engine failure.

Food for thought...

SONICBOOST

I've been drinking so bear with me... I see where you are comming from Don and I know you know a lot and all sides to this so i'm just talking. I do get your point about why would 450-500rwhp be considered safe when an engine can fail under 400rwhp, but a failed cat can happen to anybody right (FI-NA, 300rwhp-500rwhp)? Also just because the failure didn't occur at peak power does that mean the high numbers ( say 500rhwp on a stock engine) didn't put strain on the engine and eventually the engine went pop when it necessarly wasn't being taking to the top? As in your putting more strain on the engine with higher HP numbers and taking more of a chance of something going wrong even if in fact there is no direct correlation between peek numbers and engine failure.

jaguarking11

You also stated at a previous post that you had over 300runs at the strip with the stock engine without FI. A stock engine can fail with factory tune if the conditions are right.

That being said, I agree 100% with your statement.

TacoBill

+2. I agree 100%. I'm living proof.

don_w

Absolutely, running a stock engine at high levels will add to the wear and tear factor. No doubt about it. My only point is referring to the peak rwhp number as some sort of magical indicator. Seriously, other than on a dyno, how many people have actually run their car at 6500 rpm in 4th gear? And if they did, how often and for how long?

Bottom line: the stock engine has POS rods, and they can go at any time with any power adder, regardless of the peak dyno numbers.

SONICBOOST

Definently

jaguarking11

I ran my motor at 6500+ on a few top speed pulls where shifting as close to fuel cutt off was my porogative. I would say in the 6000+ rpm range she ran for at least 10seconds each run. I ended with a top speed of about 153 or so acording to my dashhawk, I bet it was in the 140+ range in reality though.

don_w

Less than 4 hours...

I wondered how long it would take for someone to actually reply to my rhetorical question...

tom281

I get it Don, and agree with what you've said. That's the basis behind what I was saying- so many people reference a number of, say, 450 but there are many examples of people running more than that without problems, and also many examples of people running less than that with failures. Again I think it has mainly to do with the tune, and still a little bit of luck and a whole bunch of common sense.

Oh to answer your question, my car crosses the line at 6500rpm in 4th...... so I see "peak" power for like, I don't know, a nano second.

don_w

LOL... same here.

BTW, you must be running 26" tires to hit 6500 rpm at 119mph. Or maybe you have 28" tires and 4.56 gears.

70MACH1OWNER

Well I know I won't be a popular guy in this thread but here goes. I have blown up a mod motor that was supercharged and it was because of the POS powdered metal rods and hyperpathic pistons that Ford uses. I agree with Don. And yes the tunes are way better now than back when I blew up but nobody can put a "NUMBER" on what is safe and not safe. And for the record...regardless of what power adder you are running you are in no danger of blowing up unless you are running at WOT. That is the danger area. Thrash you stock bottom end like Don does week in and week out and get back to us. I am still N/A and will not consider any more power mods without a forged stroker bottom end.

tom281

Last year- 275/40/17 BFG drag radials= right at 6500 in 4th at the stripe, but they wouldn't hook up so ET was like 12.4.

This year- 325/45/17 M&H racemasters and I'm no longer at 6500rpm at the line, but I now actually hook in the first three gears LOL so now a string of 11.7s at 119. This was with the factory clutch which has now been replaced with a Spec 3+ and hardened 26 spline input shaft, along with twin screw cams. I have not been to the track yet with this new combo.

I have 4.10s and a manual.


The tunes are way better now than running a canned Kenne Bell tune with octane booster in the tank LOL and trying it out at the strip..... correct me if I'm wrong but I believe that was your scenario. Still though, you're right about that magic number thing, or lack there of.