Benalbright24

hello, I am new to this forum and this is my first post. I have a 2003 Mustang GT. It has 170,000 miles and is burning oil and smokes a good bit from the exhaust pipes under acceleration. From what I've heard I think it's my rings that are bad. (If that is incorrect please inform me as I am not sure about that). I want to supercharge my car but obviously that isn't a good idea now since my motor is in need of a rebuild. My question is what steps should I take with the car to eventually have it supercharged. Money is an issue so I would like to know my most affordable options. Should I rebuild it back to stock specs, rebuild with forged internals, find a used 4.6 to drop in? I only plan to run around 350 to 400 rwhp so I don't know if I should forge it or not. It is a daily driver as of now so obviously reliability is a big thing. Thank you in advance for any advice!

Z28KLR

If you don't plan on going past 400rw then a stock rebuild would be sufficient.

However, this is a golden opportunity to do something a little better than stock. If possible to keep driving it as is for a bit while you put together $$ for forged components, that's what most would probably try to do.

Benalbright24

Thank you for your input. Another question I have is what roughly would be the price difference in a stock rebuild vs a rebuild with forged pistons and rods?

VTX1800N1

Check out my rebuild thread in this forum. We used forged pistons and rods. It's not cheap. The little things add up fast.

https://mustangforums.com/forum/4-6l...e-rebuild.html
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Soldier GT

This is a no brainier. If you plan on Supercharging your car and looking to go 350 or so to the wheels FORGE IT. I did the mistake of putting a SC on my car and not forge it and kaboom. I only put 389 to the rear wheels back then. Also I can promise you that your rwhp goals will go up and you will want more. As stated above, it will be kinda expensive (forging it) but it will most defiently pay off in the end.

VTX1800N1

Hey Soldier, I was looking at your page with your build details. It looks like you are running forged 11 cc pistons at .030 over on stock 42cc heads? Do you know for sure what compression ratio you have, and how much pressure are you able to run with the blower on what octane? I ask because my son's 2002 GT is getting 11cc .020 over forged Manley pistons as we are deciding on 38cc (11.75:1 if the calculator I used is correct) or 44cc (10.67:1) TFS heads. Down the road, he may want to supercharge it. The 38cc heads would rule that out, but it may be possible to go with a low PSI 44cc combo.

Benalbright24

Today I went to a local shop that sells engine parts and got a couple quotes for rebuild kits. The first one I got was a complete kit with Sealed Power forged pistons and Eagle forged h beam rods, the total for just parts was $1,831. I also got a quote for just a stock rebuild without the forged pistons and rods and the total was $1,423. How do these parts sound quality and price wise? I figure that I might as well spend an extra 400 bucks on the forged components. Please let me know what you think.

VTX1800N1

Unless you plan to push more than 600 crank HP, you can reuse the stock crank and get forged rods and pistons. That will save you quite a bit if that's an option on the kit you are buying.

Benalbright24

The guy at the engine place also said that having forged pistons and rods on a daily driver is a pain because the pistons expand when they get hot and you have to let the car warm up before you drive it and let it cool down before you restart it. He also mentioned that was because there was less silicone in them. I had never heard of this but he seemed to know what he was talking about.

VTX1800N1

Well, sort of. The stock pistons are hypereutectic, which just means that they are a high silicone content cast piston. The high silicon content has two benefits and one major draw back. The benefits are that it has high scuff resistance and low thermal expansion. This allows manufacturers to set the piston to wall clearance very tight and the piston will take very little wear over a long service life. The major detractor is that the silicon is never evenly distributed through the piston. High concentrations of silicon through the piston make it brittle, and any engine detonation often results in the piston shattering. This sends shards of metal through the engine, quickly destroying everything else.

A forged piston has much lower silicon content and a much more even grain structure because of the forging process. This makes it much stronger. The trade off is that the low silicon content means greater thermal expansion. Thus, the piston to wall clearance must be greater, especially when cold. This results in some piston noise on cold start and you should not drive the engine hard until it reaches operating temperature. However, that doesn't mean you can't drive it at all until it warms up. I've also never heard of the requirement to wait till a warm forged engine cools before restarting it.

The scuff resistance is also less, so the pistons will not last as long, although coatings can mitigate this.

However, forged pistons do not shatter like hypereutectic pistons under detonation. Their ring lands are also much stronger, thus forged pistons can handle much higher power levels.

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