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scxr7
04-29-2009, 07:16 PM
This happened a little while ago. at my local track. (PBIR, formerly moroso). I finished swapping a 1994 m90 onto a stock motored 1996 cougar with 140k+ miles. I ran it at the track with a baseline mail order tune. got 14.20's..not bad. but as the night went on, I kept getting slower and slower and eventually pulled off a 17.40. I came to the conclusion that, "hmm...maybe my car is going slower for a reason..maybe there is a problem".. I took it to a local dyno tuner, and the baseline pull my A:F ratio was 19:1. making 180whp. It took a while to get the tune in order since the mail order tune was so far off. eventually he got the A:F down to 12:1 and made 252whp.

After feeling all cocky and confident, I took it to the track and ripped off a 13.90 @ 97mph. I made the mistake of icing down my supercharger (I was a newb and didn't think that it could cause the case to shrink and cause the rotors to chew up the case) The rest of the night was basically all high 13's or 14.0-14.1.

Later that week, I guess piston and rod #3 got into an argument and went their seperate ways. with nowhere to go. the piston went into the head, and the rod went into the oil pan. My transmission was having a b*tch fit also, she ended up throwing up red stuff all over the place and locked up.

and to top it off. I pushed the car into a ditch on the side of the highway..by accident. literally.

Oh yes, I'll try to keep my revs down below 7k on a stock bottom end.. My tuner thought 7k would be a good idea to set the rev limiter at. ohhh welll.

Time to come back stronger and faster.

thunderkid84
04-29-2009, 08:39 PM
good time. what was all done to it when you hit 13.9 ?

89tird
04-29-2009, 10:05 PM
good times, sorry about the loss..nice to see another south florida member..:cool:

superdadsc
04-29-2009, 10:38 PM
Good Job, sorry about the rebuild. 7k is aweful high. These motors aren't known to be happy up top and w/ a stock cam and heads your peak is probably around 6k

Faster, stronger Give Dave D, XR7Dave a email and get some parts. I will be getting a rebuild kit this summer!

Stephen

scxr7
04-30-2009, 12:03 AM
I've been looking EVERYWHERE for a S/C bottom end rebuild kit. I can only find n/a rebuild kits. If you could tell me where this hidden treasure might be, I'd be very greatful. I can rebuild/build up my s/c bottom end, while I try not to blow up my new motor that I'm getting this friday.

also, to the questions about what mods I did..you wouldn't believe me..

I put the supercharger from a 1994 tbird onto a 96 cougar. I didn't swap motors. I used the stock 36lb injectors and a 255 fuel pump. also, I rigged up my own exhaust. I took a saw, cut off the exhaust where it meets into a "Y" for the n/a cars, and I basically welded two seperate magnaflows onto each pipe. its ghetto but actually it sounds decent.

so with just the m90 and exhaust, I made 252whp and ran 13.9 I was surprised that my heavy boat of a cougar could go that quick. I was using the stock 4r70w. stock street tires/rims. nothing else done. I removed the spare tire though.

I just bought an mpx clone with a fmic and 25% overdrive. I'm going to put that onto another N/A bottom end, and see how it goes. Maybe 300whp??:D The only reason I don't want to use a s/c bottom end right now is because of the compression ratio difference. when my last motor blew, the pistons were near perfect. there was no pitting or signs of damage except for #3 which hit the cylinder head.

Does anyone else go to P.B.I.R.? I saw a few guys are from south florida on here.

phesterzBird
04-30-2009, 12:15 AM
[QUOTE=scxr7;811615]
Later that week, I guess piston and rod #3 got into an argument and went their seperate ways.

Sorry to hear that but enjoyed the hell outa how you told it. :D

89tird
04-30-2009, 07:42 PM
was planning on taking my crown vic to moroso but the tailshaft blew :(

scxr7
04-30-2009, 09:19 PM
sorry to hear:( was it a PI crown vic?

89tird
04-30-2009, 09:31 PM
ya 2001 tork tech supercharged

91BlackBird
04-30-2009, 10:31 PM
No wonder the piston went seperate ways from the rod,your using a stock bottom end!!!!!
That bottom end has a cast crank and cast pistons,not good for boost at all.
I'm surprised being an sc forum no one has said this.
You will have the same brutal results if not worse if you try for 300whp on an n/a bottom end.
Do yourself a favor and don't install another n/a bottom end,find and sc one or you'll be pulling the engine again in the near future.

Super Duper Cou
04-30-2009, 10:52 PM
No wonder the piston went seperate ways from the rod,your using a stock bottom end!!!!!
That bottom end has a cast crank and cast pistons,not good for boost at all.
I'm surprised being an sc forum no one has said this.
You will have the same brutal results if not worse if you try for 300whp on an n/a bottom end.
Do yourself a favor and don't install another n/a bottom end,find and sc one or you'll be pulling the engine again in the near future.

My friends Super Coupe made like 330rwhp horsepower with a stock bottom end with 250,000 miles on it before it blew up on dyno. He blew it up on the dyno on purpose because he wanted to rebuild the motor. lol

Melon
04-30-2009, 11:03 PM
My friends Super Coupe made like 330rwhp horsepower with a stock bottom end with 250,000 miles on it before it blew up on dyno. He blew it up on the dyno on purpose because he wanted to rebuild the motor. lol

I assume he meant that the guy was using a stock N/A bottom end - judging from his post about putting a '94 blower on a '96 Cougar.

I agree - get an SC bottom end at the very least, but while it's apart - might as well upgrade.

-Melon

scxr7
04-30-2009, 11:06 PM
I know I'm new to this forum and all..but I'm going to disagree with you. stock hypercraptic pistons, and stock powder metal rods will hold, and have held, 400whp safely for extended periods of time. I'm a regular over on v6power.net and there are dozens of guys making 300+ on a stock bottom end. my buddy Ron has a single turbo setup on his completely stock engine from heads to oil pan, making 390whp running mid 11's for almost a year now.

Its all about the tuning. If you set the timing right, around 16*, with 93 octane you'll be alright. Like I said before, I tore the block down after it blew. the pistons were near perfect. The only reason the engine blew was because my tuner set the rev limiter to 7,000 RPM. I said, "thats pretty high, but I'll keep it below 5500"...pfft..yeah right. lol.

I hope I'm not sounding like a defensive jerk. I'm open to all comments. But I'm just stating that I'm not some goof that likes to blow motors. Hopefully once my mpx and fmic come in the mail, I'll have an engine to put them on, and I'll set the boost to 16 psi to start with and see if I can get close to 300whp. if not, I'll up the boost to 20psi and go again.

superdadsc
05-01-2009, 12:19 AM
A supercharger motor from what I understand put's more stress on the internals than any turbo will. 94 95 rods might be safe around 350 on an SC and if it was a turbo probably more like 450.

Stephen

91BlackBird
05-01-2009, 07:36 AM
The n/a's bottom end has cast pistons not hypers.
The sc bottom end has hypers.
Yes i agree the sc hyper pistons will handle 3-400hp but not cast pistons or cast crank for very long.
It matters not what your other pistons look like after you lost one,what did the one you lost look like.
What did you expect to see on the other pistons???????they will all look just fine until they crack and break.
You might want to have a chat with the guys on your other forum and see if they have installed new pistons,cranks or rods.
I bet most have.
You are correct on the tune,a good tune will last much longer than a bad one but not too long with cast pistons.
Cast will not stand the pressure of boost and will fail as you have found out.
You did over rev it but the pistons would have failed in time(a very short time).
If your running cast pistons you have to keep the boost under 6psi for any kind of durability,16-17 will surely cause a failure.
If you don't believe me look around the net about cast,hyper,forged pistons and boost then report back.

David Neibert
05-01-2009, 10:48 AM
The n/a's bottom end has cast pistons not hypers.
The sc bottom end has hypers.
Yes i agree the sc hyper pistons will handle 3-400hp but not cast pistons or cast crank for very long.
It matters not what your other pistons look like after you lost one,what did the one you lost look like.
What did you expect to see on the other pistons???????they will all look just fine until they crack and break.
You might want to have a chat with the guys on your other forum and see if they have installed new pistons,cranks or rods.
I bet most have.
You are correct on the tune,a good tune will last much longer than a bad one but not too long with cast pistons.
Cast will not stand the pressure of boost and will fail as you have found out.
You did over rev it but the pistons would have failed in time(a very short time).
If your running cast pistons you have to keep the boost under 6psi for any kind of durability,16-17 will surely cause a failure.
If you don't believe me look around the net about cast,hyper,forged pistons and boost then report back.

I'm using the 4.2 cast crank in my new motor. I believe it's stronger than most people here think it is, and I'm not the least bit concerned about running 20 pounds of boost. I think the pistons and rods are the weakest link on the 3.8 NA motor.

David

superdadsc
05-01-2009, 10:58 AM
Do a search or post a WTB SC motor, they are out there and you won't be disappointed!

I didn't read carefully enough! I though yo had a 95,94 SC engine! Get rid of that NA block!

There are blocks out there and get a rebuild kit and be done w/ it, just my 2cents!:cool:

Good luck with your decision!:eek:

Stephen

scxr7
05-01-2009, 12:02 PM
I have a complete 94/95 s/c engine. but the thing is, it is in pieces. I need a new crankshaft and a new oil pump..other than that its alright. I can't find a new crank for the life of me..I know the main bearing diameters are different between n/a and s/c cranks. the s/c cranks have a larger diameter.

also, to the guy that said "look at the piston that did fail". I can take a picture if you like..the piston that disconnected from the rod looked fine..It had a gouge in it from where it hit the valves. the only reason it failed was because I revved it to 7,000 RPM too many times. geez. I'm sorry but I'll prove you guys wrong here shortly. I'll make sure to post back, in the next week or so, when I get my car on the dyno with a stock n/a bottom end and stock trans.

These are pretty stout motors. If I could rebuild my 94 s/c block I would, But I can't.

DrFishbone
05-01-2009, 12:44 PM
I wonder what the final cylinder pressure is for a N/A bottom end with the 17psi of boost....compared to an SC bottom end with 17psi of boost....

QuickMustang
05-01-2009, 03:53 PM
I have a complete 94/95 s/c engine. but the thing is, it is in pieces. I need a new crankshaft and a new oil pump..other than that its alright. I can't find a new crank for the life of me..I know the main bearing diameters are different between n/a and s/c cranks. the s/c cranks have a larger diameter.

also, to the guy that said "look at the piston that did fail". I can take a picture if you like..the piston that disconnected from the rod looked fine..It had a gouge in it from where it hit the valves. the only reason it failed was because I revved it to 7,000 RPM too many times. geez. I'm sorry but I'll prove you guys wrong here shortly. I'll make sure to post back, in the next week or so, when I get my car on the dyno with a stock n/a bottom end and stock trans.

These are pretty stout motors. If I could rebuild my 94 s/c block I would, But I can't.

The only way you can ever build a powerful motor on a NA bottom end is by trying. If people always listened to doubters when they wanted to try something new/different, we would never make any progress anywhere...I'm willing to bet that 99% of the people that tell you a cast crank will break have never tried a cast crank on an SC. I don't know if it will work, but if you are willing to try, great! Go for it! And keep us up to date so we can actually see if it will work or not...

91BlackBird
05-01-2009, 07:45 PM
The cast crank is not the weak link,the pistons then the rods are,lastly if you had stronger pistons and rods the crank would be.
I understand your frustration on trying to find s/c engine parts but if your looking then this is the place to ask(post up).
No doubt your n/a bottom end will produce hp,but it will have no longevity and will more than likely part ways when you beat on it at the track(it definately will part ways with 17psi guaranteed).
However it's your car and money so i will say good luck.
Please when it happens post pics of the carnage(i asked niceley lol).

scxr7
05-02-2009, 03:55 PM
lol, I get a kick out of seeing carnage too. I'll definitely take a vid of the car when its on the dyno, and also When I'm at the track. When it blows, I want it on film :D . I'm not expecting this motor to last long. These motors can handle 400whp. but from all of those cars that are making 400 and are daily driven, they are all turbocharged. There is no doubt that a supercharger increses the stress on the engine. I'm not expecting this motor to last very long. I'm hoping it will last a month. the last one only lasted a week and a half. While I wait for the n/a motor to blow, I'll be re-building the 94 s/c motor as a spare. at least the s/c motor will last a while. maybe a few months?

Scott Long
05-03-2009, 10:52 AM
i would venture to say the weakest link is the rods on an N/A motor. Turbo's don't put stress on the snout of the crank either like the SC does and they also don't take a parasitic hp loss to spin them like an SC does.

Seriously though, 16 psi on an N/A bottom end is just asking for trouble but good luck. Seriously get it tuned. If you get any detonation that motor is done. Even with a good tune I'd be worried about bending a rod or more and trashing the pistons.

The 4.2L crank seems strong... Dave isn't the only one running one. You could go to a ford dealer and get one over the counter and then get better rods and pistons and build up your SC block and make it a 4.2L stroker. Then you will not need as much boost to make big power.