How much RWHP?

ClayStang

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Dec 9, 2008
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I was just wondering how much horsepower our cars can handle. Im looking at putting a Edelbrock E-Force supercharger on my 2005 Mustang GT. It will be a custom kit from Tillman Speed that is said to create 460 to 480 RWHP. I just want to know if the motor could handle this of would I have to upgrade the heads and/or the bottom end?

Any help would be great. Thank You
 
how much psi is that?
a safe psi is 10 or less, some say 12 is ok too, but ultimately it's your car and you have to make a decision that you can live with.

i have a stock bottom end and whipple @ 9 psi, personally i like to keep it around 450 rwhp just to be safe.
 
I wouldn't run boost at all without a pro dyno tune. At least I wouldn't do it for long and wouldn't rev over 6k. If you have a real pro tune the car you can run 450-500 rwhp fairly safe, but your engine is only as good as the weakest rod with a good pro tune.
 
I am currently running 492 RWHP at 10 psi on my Procharger DS1. Be ready to pay out the a** for a custom tune it ended up costing me a little over $600 then to make matters worse I had to pay another $175 on top of that to buy a Diablo MAFia because my MAF was pegged out. I have never understood how somebody could pay all that money for a supercharger and for the car and be happy receiving a tune via e-mail or just having there tuner shipped to them it just does not make any since.
 
The safe number that you will read over and over again from various sources (forums, magazines, ask tuners) is 450 RWHP SAE.

Beyond that you may lose a connecting rod. Yes, many guys push that to 450-500 RWHP and have had no problems, but then there are others in that range that have bent rods on display along with some piston ashtrays.

You should be fine with the Edelbrock on the stock motor. It looks to be a fine choice with a TVS design. :nice: Just get a custom tune to make sure you are not lean, and add a Kenne Bell boost-a-pump if needed. I needed one on my Roushcharger equipped car with a Steeda CAI and 2.57 pulley.
 
It's not a matter of rwhp in terms of what the motor can handle. It's a matter of how much PSI and how safe the tune is ...

I think it's a matter of all three factors combined, with the tune being the most important, followed by PSI & RWHP equally. 450 RWHP is as good a guide as any as to where to draw the line with the stock bottom end.

I had a very, very safe cusom dyno tune done for my car with daily driving in mind and my Vortech blower makes 10.5 psi at the 6,400 rpm shift points programmed into my tune. I've run the car to 6,400 rpm's dozens of times a day for 8 months now (I love boost!) and no problems to report.
 
Yes, many guys push that to 450-500 RWHP and have had no problems, but then there are others in that range that have bent rods on display along with some piston ashtrays.

Not only motor problems. There are 3 of us with forced induction that live a few miles of each other. Our cars are raced hard...other two have blown stock rearends, clutches, transmissions. and motors.

We blew the built motor on our car trying 27lbs of boost. Just finished rebuild and new mods. Going to stay at 22lbs for now....lol

Pic is of piston from my car.
View attachment 269265
 
Like I said in a previous post it depends on how strong your weakest rod is. Most importantly is the tune, but then the rods. I know Dean (twinturbosaleen) on several of the forums was at around 600rwhp with well over 100 1/4 mile passes before his popped. 450 rwhp is a good number to go with, but you have to ask yourself....Do I feel lucky...well, do ya punk? Seriously though, you really have to ask yourself how you'd react to a blown engine which will be pretty much worthless. I know I would just take it like a man and get the wallet out. I think if mine pops I'll buy a used 3 valve and just do pistons, rods and head studs and keep it under 600 rwhp.
 
You are going to be fine with that Edelbrock kit.

They designed it to bolt on and be trouble-free - it is competing with the Roush and Whipple kits.

That TVS design is so efficient it only puts out about 5 PSI to make the advertised power from what I understand.

Just make sure you get a dyno run to make sure you are not lean at WOT. If you are, a $250 Kenne Bell Boost-A-Pump will keep you safe. At around 380-400 RWHP the stock GT pump typically runs out of steam without a Boost-A-Pump.

Also - Tell Tillman you want 450 RWHP and no more.

If it is making more than that, they can install a LARGER pulley on the supercharger (larger pulley makes the S/C spin slower and therefore less boost) to drop you down to 450 or just slightly below that.
 
Just make sure you get a dyno run to make sure you are not lean at WOT. If you are, a $250 Kenne Bell Boost-A-Pump will keep you safe. At around 380-400 RWHP the stock GT pump typically runs out of steam without a Boost-A-Pump.

The KB BAP won't do anything if you have a bad tune that is running too lean.

Stock GT pumps can generally be pushed into the mid 400s with changes in the tune to effect voltage, etc to the pump and injectors.
 
It's not a matter of rwhp in terms of what the motor can handle. It's a matter of how much PSI and how safe the tune is ...

Okay I completely disagree with that statement. The amount of PSI does not determine your limit. There are lots of people at 13-14 PSI with a supercharger on stock engine. I have 12 PSI and never had any engine issues. Besides, the different superchargers/turbos create different power levels so you can't say that 12 PSI is the limit because you may be able to do 12-13 PSI on a Saleen but only 8 PSI on a turbo setup because it is more eficcient at creating cylinder pressure. Different results from different setups.

I have not seen many people blow their motors but those that have are usually running too lean, not enough octane or over-rev the engine.

The enemy is pre-detonation and you can run 500 RWHP as long as you dont start pinging from being too lean or from lower octane fuel. Dont rev the stock rods over 6200 RPM.
 
The kit i am looking at from Tillman is there upgrade to the E-Force with a 7psi pulley, bigger injectors, GT500 dual fuel pumps, and a custom tune from them. They say it should be 460 to 480 rwhp. The one problem with getting my car on a dyno is that i live in Norht Dakota and there is no shops around here that a dyno or know anything about our cars.

I am also thinking about a kit form Brenspeed and having them install it since they are only a days drive away from me, well 24 hours or so. Im thinking this because i have ordered everything from them already and are very good at taking care of there customers.

Tell me what would be the best choose. If I go with a Brenspeed kit im looking into the stage 2 or stage 3 kit. It would installed and tuned by them at there shop. If i get the Tillman Speed E-Force kit it comes with everything you need to install at home which i would more then likly do. Just to make things clear this car wont be a track demon that is always going to be racing, I just want the power for when I need it or when I want to show off. The car will still be my daily drive in the summer.
 
One other Question is does the Saleen kit come with a intergrated boost bypass valve.
Below is a list of parts included with the Tillman Speed kit and the Brenspeed kits.


Tillman Speed E-Force kit:

Tuning Tillman Speed's Exclusive SCT X3 Powerflash w/Custom Tunes
Supercharger/Intake Assembly w/15" Runners
Air Inlet With 85mm Electronic Throttle Body
41# Bosch Fuel Injectors (set of 8)
Air-to-Water Intercooler
Colder Spark Plugs (HT0)
Steel Belt Tensioner Brace
Competition Air Intake Assembly (+15RWHP!)
GT500 Dual In-Tank Fuel System
7PSI Supercharger Pulley
All Hardware and Complete Detailed Installation Instructions
Truly a FULL Supercharger System out of the box!

Brenspeed Stage 2 and Stage 3 kits:

Our turn key Saleen Stage 2 supercharger package is a complete kit that includes everything you need to support 485+ flywheel horsepower. You get the high quality Saleen twin screw supercharger producing 6.5 psi of boost (boost varies based off of RPM and altitude), 3.6 pulley and belt, a Steeda cold air intake, 39 lb. injectors, Vacuum line kit that improves fuel system efficiency, and a custom Brenspeed tuned SCT X3 programmer. This package produces an amazing performance improvement in a compact supercharger package. Although rated at 485 HP many Brenspeed customers have made over 500 HP/430+ rwhp on a stock car with this package on 93 octane fuel.

Our turn key Saleen Stage 3 supercharger package is a complete kit that includes everything you need to make 500 flywheel horsepower. You get the high quality Saleen twin screw supercharger producing 9.5 psi of boost (boost varies based off of RPM and altitude), 3.4 pulley and belt, a Steeda cold air intake, 39 lb. injectors, Kenne Bell Boost-A-Pump, Vacuum line kit that improves fuel system efficiency, HT0 spark plugs, and a custom Brenspeed tuned SCT X3 programmer. This package produces an amazing performance improvement in a compact supercharger package. Although rated at 500 HP many Brenspeed customers have made over 520 HP on a stock car running 93 octane fuel.
 
I think it is a personal preference - not an absolute "best" choice out there. If you have a safe tune and good fuel you should be fine with any of those choices. If you talk to JDM, those guys have lots of Saleen S/C cars running over 550 RWHP without a single failure.
They have been very successful with those superchargers. The EForce looks very nice too.
There are no guarantees on anything though so keep in mind a forged rotating assembly can fail too, not as easily but possible.
 
Why not go with the E-force or Saleen as is (50 state legal I assume) with their safe tune and see how you like it. You can always add more p.s.i. later if you're not happy. I'm sure both of their stock tunes have a lot of power left on the table to ensure their customers don't grenade their engines, so a good day at a dyno should pull some more power with no mechanical changes.