Progress Thread 1998 Gt Procharger Build--dyno And Track Numbers Inside

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That really doesn't sound right. I had essentially what you have, maybe a little less speed parts, on a stock internal pi motor, procharged with 12 psi, and made 400 to the wheel. I don't think having an auto instead of a stick would make that big of a decrease. Did monks have anything to say about it?
 
And let's be clear about something else too. 365 to the wheel is no laughing matter. That car will get down. In an early sn95, nobody will see that thing coming. Dont be so quick to discount the cars ability based on dyno numbers. Get out there and make some passes. These cars are lighter than coyote cars and you're putting down the same power they are. You have created probably around 415 flywheel horsepower from 281 cubic inches. That's around 1.6 hp per cubic inch. Job well done if you ask me.
 
But then again I clearly have no clue what I'm doing.
Now, stop that! I can't see anything in your posts where you've done anything wrong. Besides, Mattstang brings up a very good point about the rear wheel horsepower not being anything to sneeze at. I was erroneously thinking crank HP (old school, er, just old?). Run it down the track! What's it gonna hurt? You might be pleasantly surprised!

Nathan
 
You've got to figure were at a disadvantage with these engines because they make v6s that have more displacement than 281 ci. You've done something impressive and taken that little engine and made power comparable to the new stuff. Dynos numbers are almost always a let down. Dynos don't care how much cash you put into your build. While we're building, we get these abstract valuations of power to dollar. Its just not how it works. I know you have a strong bottom end engine. Maybe a little more boost can get you up to 400 at the wheel. How much boost you pushing on this setup and what size pulley on the blower, anyway?

You got me beat by about 40 hp at the wheel.
 
Just had a thought about the build again. The cobra pistons make 8.5 compression in a terminator engine before boost. I wonder if the lower compression of the pistons makes the difference. Stock 2v PI engine makes about 9.5 compression. If that's the case, more boost or a hundred shot may get you where you want the car to be. Hmmm.....
 
Well I sent the car off to have the motor built. I'm down anyway, had my acl replaced 10 days ago and can't exactly sling wrenches right now.

I'll update again once sit runs and is tuned.

I think we are going back with 11:1 compression and steel rings this time to squeeze every pony out of this turd.

Yay for motor three. :(
 
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That's the spirit. I know this hobby can be disheartening. When it finally gets right, you'll be glad you persevered. It will be fun to drive and you can have a great story for the car shows.

It even took the wind out of my sails to hear the second motor bit it.

Knocked down twice but still getting up for the next round.
 
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So to recap a bit. On the Dyno it wouldn't make any power no matter how the timing or fuel was setup. During the pre test it only made 130psi cranking compression in all cylinders.

On the Dyno on the last hit it lost the lash adjuster. Number one intake iirc.

Got it home and spent the better part of a day replacing that side with super car adjusters. Took it on a test drive and after two soft hits the oil pressure gauge woulfd come on and off based upon rpm. Below 3k it didn't register any and above it had enough to make the stock dummy gauge work. Sat it in the garage and sent it off on a roll back to a trusted friends shop. He tested the oil system and it has or had 42psi warm at idle but was bleeding pressure off quickly.

He thinks my pickup tube cracked or is leaking (yes I put in a new pump and new o rings). He said he's seen it before on the older stock tubes. They'll develop a crack and start bleeding pressure.

He was able to yank the motor last night but not tear it down yet. Still likely going to swap Pistons as the used 03/04 assembly I bought had no markings on the Pistons. I don't think they are a stock cobra piston as the cranking compression indicated a much lower static than it should have. Likely more in line with 8:1 vs the expected 9.5:1 we were shooting for.


The end goal is still the same to crack 500rwhp and bust into the 10s with it.

Time will tell. I really just want to enjoy the car. I've put 200ish miles on it since sept of last year.
 
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I'm finally able to hobble around a bit since my knee surgery 6 weeks ago.

We tore down the engine and here is what we found:

#2 piston had the second ring broken in half. No signs as to where and how it exited the engine. There are no marks in the cylinder wall, no marks on the piston, no broken ring lands etc, and no marks on the heads or valves. It's just effin gone. Weird.

#2 cylinder also appears to have been mis-machined by the machine shop. I don't remember exactly now but I think it measured .0040 bigger than it's supposed to be. (I may have a zero in the wrong place)

#2 main bearing was chewed up while the front and rear (thrust) were in perfect shape. Indicates a bent crank and that likely caused collateral damage to the block.

The rods and pistons were not what I was sold. I was sold 8 80k take out 03/04 cobra rods and pistons. The rods are what they say they are although after some number ID running they are 3 different generations, which means the seller pieced together a full kit from various cars. The pistons have 4 different ID number (Shame on me for not seeing this before install) and 3 of them are not forged. Those three were jacked up. They all looked almost identical to the naked eye and I had no reason going in to second guess them (first mod motor build). If I knew then what I know now... ugh.

The bearings had two different batch dates. (rod bearings). 7 from 2015 and 1 from 2016. All the 2015 ones were chewed up, the 2016 looked perfect. Very odd. These came from summit racing all at the same time.

The heads have an internal crack in the oil passage ways and we've decided to junk both of them due to all of the prior issues with this set of heads. ugh.

The only thing we can salvage are the full assortment of ARP bolts and the todd warren blower cams.

So I'll be selling the blower cams and putting in a stock pi 2v and just enjoy the damn car. Screw this hunt for power and the money/let downs associated with it. It's just not worth it and I want to drive the dang car.

The good news is the bearings we were able to check were spot on for clearances so it doesn't appear that any of this was my fault (other than not cross referencing the pistons).



Hopefully we have it going in the next couple of weeks. I think we are going to leave the blower on it and a safe tune. I'll be happy with 400rwhp all day long as long as it's reliable.
 
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