Does the fuse pull work for tuned cars? Losing 100+ hp

[Aqua Blue RS/SS]

I’d be willing to bet your exhaust has at least a little to do with it, stock cats and boost can’t be a very good combo. It needs to be able to breath.

[V8only]

Originally Posted by race24x

OK a couple of things. First a Mustang Dyno has to have inputs. I am not sure I agree with entering the weigh of the vehicle and allowing the dyno to figure aerodynamic drag as part of a HP calculation. Some may argue a Mustang dyno is better, I am not sure I agree. regardless off the weight of your car 460 crank HP is the same in a semi truck as it is in a Corvette. Of course the Vette is faster its lighter but the HP is the same. This is just my understanding from reading how they work, I am no expert. So if they accidentally entered the wrong variables you can be showing more or less than what you really are. HOWEVER my Kraftwerks kit with the stock pulley made 5.4 PSI and 481 rwhp on a Land and Sea Dyno (which is supposedly very similar to a Dynojet) With about the same amount of boost you made 460 rwhp. My tune was an Email tune at that point. We did a run to see what our base was. These are centrifugal SC and you have to spin them up. You wont even make boost until 4500 and that is why I bought a 75mm top gear. It moved the power down to about 3900 I was making the same 481 rwhp at 4750 and max rwhp went to 543 rwhp. The improvement was very noticeable and you will find JRE wont even sell the kit with the 80mm pulley. They where allot of help to get me to a better place. JRE FPCM and a ZL1 fuel pump are needed for this level. Next I thought well if 5mm made almost 2psi more and movee the power curve a 70mm would be even better right..... Why yes it was. Now I make 300rwp @3200 before 300rwhp@3300 400rwhp@4100 before 400rwhp@4250 500rwhp@4650 before 500rwhp@5500 and 589 rwhp@6200. You can see it moved the whole power curve down. If you have the stock pulley start the roll on at 4500, turn your car up to 6500 and you should pull away easy. Your basically not making any boost. You should have a boost gauge and AFR gauge. I have the same car with the same M6, ZL1 11" wheels with Goodyear 305/35/20s and it will break the tires loose in second gear just by applying pressure to the go pedal. It would not do that before. A stock SS isnt even close, you just need to spin the SC faster sooner. Just remember with a 70mm pulley bring your rev limit down to 6200 that is the limit according to the guys at Kraftwerks. OH I have a used 75mm pulley if you want to try it. My injectors maxed out at 90% on the 75mm pulley, but handled it alright.

Man, thanks so much for this info. I assume you upgraded the injectors with the 70 mm pulley? Do you have the part # for that 70? do you want to sell the 75? I'm not ready to upgrade the injectors yet, but I will upgrade to a zl1 pump so I can at least run the 76. Having the power up so high doesn't do crap for me lol.

[race24x]

I can sell you the 75mm that will help and you can keep the 550 Grams injectors that came with the kit. You will need the ZL1 fuel pump and a JRE FPCM. That will bring the power down some and make it useable. I had to upgrade the injectors and modify the adjuster bolt for the 70mm pulley and lower the limiter to 6200. I dont have the part number for the 70mm pulley I called Kraftwerks direct and ordered it.

[race24x]

Here is the 80mm to 75mm Dyno sheet. Sorry about my scribbles. I was working on comparisons and what it would possibly be with the 70mm pulley.