Need help with speed density!!!!

XXXX_Big_Daddy_XXXX · Dec 6, 2011

Dude ur very experienced and super smart.I'm really glad I found this site.Thanks everyone!!!

2000xp8 · Dec 6, 2011

Here's a question i don't think anyone has asked.
Are you after 300 rear wheel hp or 300 flywheel hp?
Me personally i see no use for flywheel numbers since it's really not something that can easily be measured.

There is a pretty big difference in the two readings.
For the record, most discussions here that take place will involve rwhp numbers.

XXXX_Big_Daddy_XXXX · Dec 6, 2011

I'd love to have 300 rwhp but I'll take 300 flywheel or crank..lol...I think 300 would be great and would satisfy me

XXXX_Big_Daddy_XXXX · Dec 6, 2011

well looks like thanks to you guys I've now got a plan together.I figured I'd run it past you guys a last time to make sure.I am leaving it SD with the SD computer,gt40 upper/lower intake,24lb injectors,gt40p heads,long tube headers,65mm throttle body,stock cam,bore 30 over,AC and smog delete and under drive pullies...I'd like to just run this past everyone one last before I start buying parts and realize I've got something messed up or bought a wrong part.like I've said a 100 times and I'm saying again,thanks to everyones advice and help.I really appreciate everyone that's taken the time to lend a helping hand to a complete stranger.If there's anything in my list thats not right or won't work please let me know.I'm going to wait a few days to see if there's something I'm missing or if anyone disagrees with the part list I've composed....thanks

Noobz347 · Dec 6, 2011

I would ditch the under drive pulleys and go with a 3G alternator upgrade and electric fan. UD pulleys aren't really worth a crap on a 5oh.

--also-- Don't forget to get an adjustable fuel pressure regulator

XXXX_Big_Daddy_XXXX · Dec 6, 2011

oh yes,thanks noobz for reminding me.I was going to ask how to program the computer or what type of chip do I need to install.I've never heard of a 3G alternator but I'll defiantly research it. .Do I just measure the belt needed when I delete the AC,smog and fan?

5.0Droptop · Dec 6, 2011

I ran thumpers ported e7 heads cobra intake Tmoss ported the lower comp cams nx264hr cam 24# injs full exhaust etc. all on speed desity with no issues.

Another member here had a 347 built with mild cam. Made good hp and. Tq and was SD

Another member ran a kennybell sc on sd list goes on. It can be done.

aar0s · Dec 6, 2011

why not run the 3g with the e-fan and underdrives, they are worth as much on a 5.0 as they are on a 4.6. If it will give him the extra 5 hp to get him to his goal and you've got most of the front taken apart doing the fan and alt might as well put them on too.

Noobz347 · Dec 6, 2011

XXXX_Big_Daddy_XXXX said:
oh yes,thanks noobz for reminding me.I was going to ask how to program the computer or what type of chip do I need to install.I've never heard of a 3G alternator but I'll defiantly research it. .Do I just measure the belt needed when I delete the AC,smog and fan?

You can wrap a non-stretchy string or wire around your pulleys and measure that to get the belt length...

--or--

You can do a search for belt length. A lot of accessory combination have been measured a TON of times in these forums and the answer is probably already out there. Diagrams on belt routing as well.

Noobz347 · Dec 6, 2011

aar0s said:
why not run the 3g with the e-fan and underdrives, they are worth as much on a 5.0 as they are on a 4.6. If it will give him the extra 5 hp to get him to his goal and you've got most of the front taken apart doing the fan and alt might as well put them on too.

You will not get 5 RWHP from that combo. If you completely removed your ser belt from a 5oh on the dyno, you MIGHT see 6 HP. With the A/C, and smog pump already removed, you're just driving the power steering, fan, and alternator with a 20% under drive. That not worth 5 HP to the wheels.

Not to mention that the OEM alternator is only 85 amp at power. Less at idle. Under driving that alternator will likely cause electrical issues. Adding more HP while slowing the fan and water pump has the potential to cause even more issues.

If you're talking about running an electric fan AND under drive pulleys then the HP benefit is even LESS.

Blown88GT · Dec 7, 2011

See my website for 3G info.

aar0s · Dec 7, 2011

not talking about running the oem alt. but... how do you figure the its not worth runing a 3g alt, efan and underdrives?

Noobz347 · Dec 7, 2011

aar0s said:
not talking about running the oem alt. but... how do you figure the its not worth runing a 3g alt, efan and underdirves?

Noobz347 said:
You will not get 5 RWHP from that combo. If you completely removed your ser belt from a 5oh on the dyno, you MIGHT see 6 HP. With the A/C, and smog pump already removed, you're just driving the power steering, fan, and alternator with a 20% under drive. That not worth 5 HP to the wheels.

Not to mention that the OEM alternator is only 85 amp at power. Less at idle. Under driving that alternator will likely cause electrical issues. Adding more HP while slowing the fan and water pump has the potential to cause even more issues.

If you're talking about running an electric fan AND under drive pulleys then the HP benefit is even LESS.

I try another way. A bone stock 5oh. Put it on the dyno. Do a pull. Shut it down and remove the serpantine belt (this has been done BTW). The result is a gain of approximately 6 RWHP (I read one test where there was difference of 12 RWHP but the car had been removed and put back on the dyno). That's it. The crank is not driving any accessories.

Now... install a set of under drive pulleys. They are 20% under drive. So take 20% of even the HIGH number. That's 2.4 RWHP.

Now... let's take the fan out of the equation (no longer being powered by the pulley system)
Let's take the smog pump out of the system (no longer being powered by the pulley system)
Let's take the A/C out of the system (no longer being powered by the pulley system)

We're left with power steering, water pump, and alternator... Oh... and a 20% under drive set of pulleys. Again... So instead of that 2.4 HP RWHP gain, what do we actually have since we're only powering those last 3 accessories. Ontop of that, we're slowing the water pump and alternator.

There's a reason why you see these silly pulleys every other day in the classifieds. They generally cause more problems than they free HP.

aar0s · Dec 7, 2011

and im saying that if he's doing the 3g alt and going to have the fan off to switch to the e-fan and he's trying to squeeze everything he can out of it then might as well put them on. the 3g will take care of any charging problems, ive ran a set for years and never had a cooling problem that was caused from the water pump pulley being underdriven. The OP can do what they want, I say pick up a set on the classifieds and try it.

MY 85 GT · Dec 7, 2011

To the OP post I run boost thru a speed density 87 Mustang..Actually i run 10 psi and a snow meth injection Kit...On a stock long block...with a heavy Vert AOD car running 3.55's 1st time out i ran a 13.3 car weighing with me in it 3780 lbs with In the driveway tunning Locked timing and FMU...The car has high 12's in it,I was running the meth to rich and the timing was to low thats all fixed but tracks are closed here in NJ...I will run her next yr...

FastDriver · Dec 7, 2011

OP to do it right, either convert to mass-air, or pay for a tune (any chip your tuner prefers), or learn to tune it yourself and buy a TWEECER RT, or Moates quarterhorse

Cobra912 · Dec 8, 2011

I'm pretty sure a lot of guys used the same cam I had before with SD, the comp cams NX264HR. great lumpy idle, lots of power. I believe around .512 lift

Might be an idea.

Need help with speed density!!!!

XXXX_Big_Daddy_XXXX

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2000xp8

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XXXX_Big_Daddy_XXXX

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