Supercharger vs. N/A build!

[Bernica]

What state are you in that's making you use the cats? Curious...

[Cobrat24]

Originally Posted by Bernica

What state are you in that's making you use the cats? Curious...

I'm in Nevada but bought the cobra from a gentleman in Utah who had them on it.

[Bernica]

Originally Posted by Cobrat24

I'm in Nevada but bought the cobra from a gentleman in Utah who had them on it.

Check Nevada laws for registering specially constructed vehicles. You may not need them. Plenty of guys here that may know the rules there..

[Cobrat24]

Originally Posted by Bernica

Check Nevada laws for registering specially constructed vehicles. You may not need them. Plenty of guys here that may know the rules there..

I don't need them in our state and its registered as a classic vehicle with no smog requirements. Which is why I'm changing this setup along with the motor setup. Can't wait but man I don't know how he previous owner drove it the way it was for so long.

[Bernica]

During your build (or re-build) lost those cats!
Every time I see them on a Cobra it is irritating.

[Cobrat24]

Oh trust me they are not going back on.

[Cobrat24]

You guys want to know why it made only 243hp?

[ct clint]

There's a lot going on there did no one do leak down test or read the plugs ? The cats are another story. I think u will be in for a big surprise with just a fresh well set up motor. Can't wait to see how it turns out best thread in a while

[Shootnride]

[quote=Cobrat24;1377612]You guys want to know why it made only 243hp?[/QUOTE

Those marks on the piston look like a bit of valve interference. Got some bent valves ?

Ted

[Cobrat24]

Ok so what I found out from the previous owner, Engine is an 86. Top end and cam were added and has new bearings. The guy did the gtp 40 heads but didn't check clearances. He was told it would bolt right up.

Not a big deal as we were already junking the heads and pistons anyways. I'll be taking photos of the heads and cam comparisons too.

Stay tuned!

[Bernica]

You have issues far beyond my attempt at any explanation. But it certainly explains a few things!
Good luck and keep us all posted.

[Cobrat24]

Originally Posted by ct clint

There's a lot going on there did no one do leak down test or read the plugs ? The cats are another story. I think u will be in for a big surprise with just a fresh well set up motor. Can't wait to see how it turns out best thread in a while

Yeah it's weird because the car was done right chassis wise but then the motor setup the more we get into it , the more we realize this guy shouldn't be working on his own $hit.

His reasoning for the cats were to quiet the car down. The guy is 67 yrs old and was wearing ear plugs when he drove it.

[Bernica]

I'll take a shot and say carbonized everything due to running rich.

[Gaz64]

Sorry to see the valve to piston contact.

Clearly a case of poor assembly on behalf of the previous owner.

How many other pistons also kissed?

Was the engine ever misfiring?

Some poor combustion/quench characteristics there, only about 90% colour on some pistons.

Will you stay with the same cam?

Gary

[Cobrat24]

Originally Posted by Gaz64

Sorry to see the valve to piston contact.

Clearly a case of poor assembly on behalf of the previous owner.

How many other pistons also kissed?

Was the engine ever misfiring?

Some poor combustion/quench characteristics there, only about 90% colour on some pistons.

Will you stay with the same cam?

Gary

It was never misfiring the 3 months I was able to drive it before we had snow. But 6 out of the 8 Pistons have marks. I'm sure if I had a full summer driving this it would have grenaded on me. Better to catch it now.

I'm going to post pictures of the new cam vs the old cam with the specs. Same with the heads. Everything in this motor is very very mild when this guy put it together. Honestly I can't believe I couldn't hear it when it was running.

[Slo-poke]

Crate Coyote! ? maybe a engine from a Shelby gt 500, both will fit, the GT 500 can be boosted to unreal figures and is still well mannered on the street
Me= 429 cobra jet, 500hp or more. but heavy!

[twobjshelbys]

Originally Posted by Cobrat24

You guys want to know why it made only 243hp?

Well, that sure solves the mystery. Once fixed (and exhaust cats gone) you should be a lot happier!

[cycleguy55]

Originally Posted by Cobrat24

Just a heads up, thanks for all the advice and suggestions. My mech picked up the cobra, it goes in today for dyno before he work begins. We wanna see what it puts down at my elevation verses the elevation from where I picked it up. I'll keep you guys posted on the numbers. I'm anticipating a low hp/tq number.

I think the item I'm most excited to see is the exhaust build. My guy will be fabricating my headers and is working with Borla for the custom side pipe fit. Goal is 3.5 inch pipes into the side pipes. He hasn't disclosed the heads or cam combo but he's matching the flow rate, which is why he is changing the exhaust. I can't wait to see this setup. I will post pictures as they come along.

Came to terms with using what I have. And working on a different build down the road when I can really afford the bigger motor.

No problem with that. One Web site that's interesting to play with is Camquest.com - it's clearly set up to sell Comp Cams products, but you can play with different combinations to get an idea of what to expect with HP, torque, when it's going to peak, etc. Is it 100% accurate? Not likely, but that's not the point - the point is to be able to select different options and see the effect those changes have on the overall result - relatively speaking, of course.

For example, I selected a 351W (close to a 302 stroked to 347 CID), and a cam with some specs to give you solid street performance (RPM Range: 2200 - 6200, Grind: 280HR, Duration @ 0.050" 224/230, Valve Lift: 0.560 / 0.598) and with good heads the Camquest tool shows >450 HP and almost 440 ft./lbs of torque. With a manual transmission that's nearly 400 RWHP.

I'm curious about the use of Borla mufflers between your exhaust manifolds / shorty headers and the side pipes. Obviously short, straight-through mufflers will be much better than catalytic converters, but why not just straight pipes? For that matter, why not go to headers between your engine and the side-pipes?

BTW, which side pipes are those, and have you checked them to see how much restriction is in them?

Perhaps worth checking out is this thread (Classic Roadster exhaust dilemma), the photos starting at post #20 show a re-build of side pipes with new, larger core mufflers to open them up.

[Cobrat24]

Originally Posted by cycleguy55

I'm curious about the use of Borla mufflers between your exhaust manifolds / shorty headers and the side pipes. Obviously short, straight-through mufflers will be much better than catalytic converters, but why not just straight pipes? For that matter, why not go to headers between your engine and the side-pipes?

BTW, which side pipes are those, and have you checked them to see how much restriction is in them?

Perhaps worth checking out is this thread (Classic Roadster exhaust dilemma), the photos starting at post #20 show a re-build of side pipes with new, larger core mufflers to open them up.

Ok so to answer your question, as we all know the existing side pipe setup from the primary's to the collectors are very restrictive, not to mention within the actual sidepipe itself. The idea with this is, headers to high flow borla exhaust and borla to straight pipe no restrictions. This flows better than the exhaust with side pipe setup that is offer currently. I know there are others out there that take care of the sidepipe itself but no one offers an alternative to the collector issues from header to side pipe. If you look at those collectors , a 2 inch primary times 4 is squeezed down to really a 1 inch through that collector.

[Cobrat24]

Now the new collector setup Next to the old.

Muffler will bolt to this directly.