motor build questions

[01BlueCobraVert]

OK, so my motor took a shit @ 34,000 miles. A piston exploded when my reluctor wheel came off the keyway... :shrug:
I am building it up but I am staying N/A until I pay the car off.
My crank is good and my heads are ok.

My build consists of:
1.) stock crank
2.) Manley H-Beam rods
3.) Manley pistons (I need to know if I should use 11cc "around 9.2 compression" or 18cc "around 8.6 compression")
4.) stock heads I am debating on porting. "stage 1-2 for $225 a head"
5.) older naz ported mach 1 intake
6.) BBk L/T's
7.) Fidanza aluminum flywheel

I need to determine if I should go with the higher or lower compression ratio and if it is worth porting the heads. I plan on a Kennebell in about 2 years. I also got the accufab TB and I am interested to see if I gain 1 HP or loose 5 HP from installing it. LOL ( I got it for 50 bucks)

Thanks for any input.

 

[cobraracer46]

There is nothing wrong with a Kenny Bell Supercharger, but if you stuff your short block with 8:1 compression pistons and then drive your car around on that set up for two years while you wait for the KB you will end up shooting yourself in the foot because you will have a dog of a car with no torque.:fart:

I would go with flat top pistons and then bolt a centri style blower.:burnout:

 

[droptopsnake01]

9.2 compression.

 

[gmsux]

2 years before FI, if you still own the car... I'd go stock compression and plan for a centri.

 

[Darkc0bra]

^^ I agree completely there. They have a hard enough time grabbing low end stock but if you change it to low compression with no KB, it wouldn't be pretty. Might as well hang it up for a Import LOL JKJK but seriously, stay closer to stock with a Centri Blower later. You won't regret it. You can always change it later

 

[qwik01cobra]

9.2 compression.

thats pretty close to the compression im at and the car made 310 on a base tune with the same set up if that helps at all.

 

[01BlueCobraVert]

Thanks for the input. I never plan on getting rid of the car which is why I am planning for the future. I already did a full suspension, aluminum bushing setup, kenny brown matrix brace kit, 4.10's, irs braces, 03/04 halfshafts, etc...

If I went with the lower compression do you think I would still hit 300 rwhp? I put 4-5K on the car a year which is from mostly highway driving. Wouldn't the gears help make up for the loss of torque? Thanks

 

[97desertCobra]

Thanks for the input. I never plan on getting rid of the car which is why I am planning for the future. I already did a full suspension, aluminum bushing setup, kenny brown matrix brace kit, 4.10's, irs braces, 03/04 halfshafts, etc...

If I went with the lower compression do you think I would still hit 300 rwhp? I put 4-5K on the car a year which is from mostly highway driving. Wouldn't the gears help make up for the loss of torque? Thanks

Yes the gears will help but for every 1 point in compression increase you will gain about 5% increase in power and torque. I can't remember the exact compression for stock 99-01 Cobra's but for 96-98 its 9.85.1. If I were to drop down to 8.8.1 and keep everything the same its very likely that I would lose about 5% of my horse power and torque. That may not sound like such a big deal being just 5% but our DOHC engines already suffer from lack of low rpm power and torque.

So just an example, if you make 300rwhp as you are now and then drop to 8.8.1 compression and leave everything the same, then you would probably make 285rwhp.

I would stay as close to stock compression if I were you, that way the car does not feel sluggish. Centi blowers also take well to increased compression more so than PD blowers due to the fact that centri blowers generate less heat.

 

[Darkc0bra]

I can't remember the exact compression for stock 99-01 Cobra's but for 96-98 its 9.85.1. If I were to drop down to 8.8.1 and keep everything the same its very likely that I would lose about 5% of my horse power and torque.

They have the same compression as the 96-98 Cobras, 9.85:1

I completely agree just stay closer to stock compression. As I said early and what desertcobra said, you will suffer greatly from low end power and torque loss. Well not greatly but you will feel the difference. :bash: