My 05 GT, GT500 swap build thread

[19COBRA93]

Got the 4.0L on, and dyno'd it.

The plan was to put this on now before building the motor so I could compare it directly to the 2.9L with no other changes. Everything is the same as with the 2.9. Same tune, same dyno, same everything except the blower itself.

Unfortunately, I didn't have a large enough pulley to keep the boost down to 23-24lbs as with the 2.9L, so it is making about 1.5-2 lbs more boost than before. With that considered, the difference is still very dramatic. It feels like a very different car.

It made 874/800 at the wheels on 25lbs (15% lower + 3.5" upper), 19 degrees timing, and 100 octane + torco, stock motor. The biggest gain was the torque all through the RPM band, which is exactly what I was looking for. I always felt the 2.9L didn't quite make the torque I wanted it to. So I gained 50rwh and 111rwt with just the blower swap.

Next up is a built motor and nasty custom cams. I'm expecting another 80-120rwh from the cams and higher RPM capability.

Here is the graph showing the 2.9L numbers (in green) and the new 4.0L numbers:

 

[skwerl]

Holy shit!

 

[Mike K]

FUCK! Those are some great numbers.

 

[Department Of Boost]

HaHa! Sweet!

And people keep trying to tell me that the bigger blowers hurt torque. Mmmmmmm, not so much.

 

[07TGGT]

HaHa! Sweet!

And people keep trying to tell me that the bigger blowers hurt torque. Mmmmmmm, not so much.

How do they figure that? Especially with a PD blower? I mean, it's common knowledge that larger displacement motors produce more TQ, especially down low, than smaller displacement motors... Same concept for a PD blower.

 

[05yellowgt]

How do they figure that? Especially with a PD blower? I mean, it's common knowledge that larger displacement motors produce more TQ, especially down low, than smaller displacement motors... Same concept for a PD blower.

Believe the thought process is that a smaller pd blower pulled to the same boost level as a larger blower will make more torque down low since it is being spun higher. Or they are going back to the days of a pulled eaton vs a twin screw on 03-04 cobras. It was very common to over spin the piss out of the stock eaton which resulted in higher torque than horsepower numbers because the eaton was so far out of its efficiency range that it ran out of steam well before the motor was done rev'ing.

Modern twin screw and tvs blowers don't exhibit this behavior due to much better head units and intake systems.

 

[Department Of Boost]

How do they figure that? Especially with a PD blower? I mean, it's common knowledge that larger displacement motors produce more TQ, especially down low, than smaller displacement motors... Same concept for a PD blower.

I'm sure it is like most bad assumptions out there. If enough people repeat it enough it becomes fact.

Not very many people try to understand things for themselves anymore.

 

[BruceH]

Got the 4.0L on, and dyno'd it.

The plan was to put this on now before building the motor so I could compare it directly to the 2.9L with no other changes. Everything is the same as with the 2.9. Same tune, same dyno, same everything except the blower itself.

Unfortunately, I didn't have a large enough pulley to keep the boost down to 23-24lbs as with the 2.9L, so it is making about 1.5-2 lbs more boost than before. With that considered, the difference is still very dramatic. It feels like a very different car.

It made 874/800 at the wheels on 25lbs (15% lower + 3.5" upper), 19 degrees timing, and 100 octane + torco, stock motor. The biggest gain was the torque all through the RPM band, which is exactly what I was looking for. I always felt the 2.9L didn't quite make the torque I wanted it to. So I gained 50rwh and 111rwt with just the blower swap.

Next up is a built motor and nasty custom cams. I'm expecting another 80-120rwh from the cams and higher RPM capability.

Here is the graph showing the 2.9L numbers (in green) and the new 4.0L numbers:

Wow! That's really something. Congrats.

I'm sure it is like most bad assumptions out there. If enough people repeat it enough it becomes fact.

Not very many people try to understand things for themselves anymore.

This is all too true. Personal experience is underrated nowadays.

 

[GallopingFord]

I really want this. I don't need it but I want it.

Very nice numbers!

 

[lito]

Nice, Michael@LM has awesome grinds for that combo, like the ones that ran on the mile 22x. Higher lift than the heads allow so some work on the head is needed. Give him a call.

 

[19COBRA93]

HaHa! Sweet!

And people keep trying to tell me that the bigger blowers hurt torque. Mmmmmmm, not so much.

I've been hearing that for a while, and I've always disagreed. I think it stems from a few things, like cams, and heads, and intakes. Most of those things negatively effect low end torque when you go real big. People get that in their mind and just assume it applies to all things. I also agree with your 03/04 cobra eaton suggestion. That's also why there's the myth of "lower pullies add torque".

I'm sure it is like most bad assumptions out there. If enough people repeat it enough it becomes fact.

Not very many people try to understand things for themselves anymore.

There's a lot of this going on over on SVTP. One person mentions something in a thread, or heard something, or has a buddy who... Then it spreads through the forums and somehow becomes fact.

I really want this. I don't need it but I want it.

Very nice numbers!

Nobody needs this. But it's okay to want.

Nice, Michael@LM has awesome grinds for that combo, like the ones that ran on the mile 22x. Higher lift than the heads allow so some work on the head is needed. Give him a call.

I already have a set of custom Bullets for this combo waiting to go in. They're pretty aggressive, so they should do pretty well. Probably not as big as what you're describing though. It's still a daily driver (sunny days), so I need to keep it more on the tame side.

 

[Surfstang2020]

Very nice impressive
Numbers for sure

 

[GallopingFord]

Nobody needs this. But it's okay to want.

You are very right lol.

 

[avinaj80]

Got the 4.0L on, and dyno'd it.

The plan was to put this on now before building the motor so I could compare it directly to the 2.9L with no other changes. Everything is the same as with the 2.9. Same tune, same dyno, same everything except the blower itself.

Unfortunately, I didn't have a large enough pulley to keep the boost down to 23-24lbs as with the 2.9L, so it is making about 1.5-2 lbs more boost than before. With that considered, the difference is still very dramatic. It feels like a very different car.

It made 874/800 at the wheels on 25lbs (15% lower + 3.5" upper), 19 degrees timing, and 100 octane + torco, stock motor. The biggest gain was the torque all through the RPM band, which is exactly what I was looking for. I always felt the 2.9L didn't quite make the torque I wanted it to. So I gained 50rwh and 111rwt with just the blower swap.

Next up is a built motor and nasty custom cams. I'm expecting another 80-120rwh from the cams and higher RPM capability.

Here is the graph showing the 2.9L numbers (in green) and the new 4.0L numbers:

I just threw up in my mouth a little... Nice numbers man! Your build is truly inspiring.

 

[19COBRA93]

Well the tear down has begun. Got the motor out last night. Should have the rotating assembly to the machine shop tomorrow. Hoping to start putting it back together by the weekend. It's getting Billet rods, custom cams, springs/retainers, a '13 GT500 oil pan, and billet steel oil pump gears.

 

[Sky Render]

Holy crap, this is a sweet build.

You still liking your Truetrac?

 

[19COBRA93]

Holy crap, this is a sweet build.

You still liking your Truetrac?

Yes, it's one of my favorite mods. It's performed flawlessly. I'm going to be upgrading to 33 spline axles soon, and I'm about to order a 33 spline Truetrac to go with them.

 

[Department Of Boost]

Wow, you got it out with the headers on there?

 

[19COBRA93]

Wow, you got it out with the headers on there?

Hell yeah I did. That's how I roll. lol. I personally find it's less work to pull it as a whole assembly. I did have to pull the blower off first, but otherwise it came out exactly as you see it. All by myself too. It goes in the same way. It should be easier going in this time, as I'm installing a BMR K-member while it's out.

 

[Mystickeith50]

I approve....please continue.