99 Gt Turbo Project


Feb 18, 2016
I'm new to these forums but figured I'd share my project I have been working on for the past couple years and introduce myself. I purchased a 99 Mustang from Florida with an On3 Performace turbo kit. Car was running a Master Power S70 turbo. Engine built by Al Papitto from Boss 330 Racing. Engine block was swapped for the aluminum over the Iron block. Has a cobra crank, Manley H beams, Diamond 19cc pistons (Built as 8:1 Comp.), Arp studs, Comp cams springs, Ported Heads, No cam, BBK 80mm Throttle Body, Pro M MAF, High Volume Oil Pump, On3 Turbo Piping. The fuel system is a cobra dual pump with the Kenne Bell Boost-a-pump and 50lb injectors. Was running on stock trans with a bad 3rd gear whine. 3.08 rear end. PA Racing tubular A-Arms and K-Member.Modular Racing Coils with Koni Adjustable Shocks. Strange 10-way adjustable struts. Car was claimed to run 600hp at the crank. Soon put it on the Dyno to find it was making barely over 300WHP. This was fixed with a quick tune by Brian at Dyno Tune Motorsports here in Ohio. We made 444WHP and 531TQ and stopped due to the horrible sounds coming from the trans. Soon installed A Snow Performance stage 2 methanol Kit but never tuned on it at that time. Shortly after my tune the stock T-45 Finally had to go. Dropped the trans to find the gears were in pretty bad shape. Getting the T-45 out sucked! Since the Bell housing doesn't separate all that easy but the piping hugged the bottom the of the trans. Needless to say after a bit of work we separated the bell housing with the trans still in the car.... PAIN! Hooked up with Amp and got a T-56 Magnum Swap. Got rid of the stage 3 clutch and went with McCleod's RXT twin plate. Got A custom drive shaft from APS and a Lakewood Bell housing. Could not get the clutch to engage properly and ended up finding out the Ford Racing flywheel I purchased will not work with the swap. Soon exchanged the flywheel for one from McLeod. Ran into a few snags here and there with the starter alignment and the clutch cable. Within 200 miles of driving with the new trans the tail seal of the trans blew on the highway. I contacted Tremec and the provided me with a replacement and upgraded the seal so it would not happen again. Only got to enjoy the car for a little while longer until the front crank seal blew... Thus began the current portion of the build I am currently in....

With the new build I upgraded the Turbo to a Ball Bearing PTE 7675. Swapped out the Intercooloer for a 31"x12"x4", 4" with a core of: 24"x12"x4", Changed the radiator and brackets to make room. All new Piping was put in since the last was far to big and was loosing a lot of velocity. Put in a SCT 5000 MAF, Hypergate wastegate and a TurboSmart Boost Controller. Installed a more aggressive cam and BTR Valve Springs. Eldebrock Victor Jr. Intake and fuel rails, TrickFlow 80lb injectors, Hot Wired the pump, and installed a Morso 8qt. Oil Pan. The previous exhaust was crush bent so I installed a electric cut out and a dump.

Ran the car on the dyno to find out the fuel pump failed. Swapped out for an in-line Holley Dominator and Holley Fuel Pressure Regulator.

Ran the car some more and had failed coils. Replaced

Ran the car some more and started pushing coolant. Would only push with a good amount of boost so it wouldn't fail any tests. Pulled the heads and the gasket did let go. Send the heads out to be inspected and did a new valve and guide job. Noticed with the heads off that the cylinders were polished and were washed out at one point with the previous owner. Had the block Honed. Also replaced the Rod bolts to ARP2000s. Took advantage of the down time and had some stuff powdercoated in the engine bay. Got everything back together and put it back on the Dyno. Car was still acting up and would have a slight dip in power then would come back strong within a couple hundred Revs. Replaced literally EVERYTHING to try to get rid of it including all sensors, new injectors, new coils (again), tons of plugs and different gaps, new crank and cam sensors, new MAF, Hell even tried another 7675 turbo that I borrowed...

In the end we decided it had to be something internal. Seems like it was a little bit of valve float. Took out the BTR Springs and went with another set. Within this time I sent out my turbo to be inspected and found out it needed to be rebuilt... Currently waiting on it to come back and see if the issue is fixed. THIS HAS BEEM QUITE THE CHALLENGE!

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Wasn't a pretty sight...and I've got big hands
SN Certified Technician
Mar 2, 2015
Nice man. Welcome aboard. Guess your car has seen its share of jack stands. Lol. Very nice build. I'm going turbo in my notch one day. Once my pockets grow up. Smh. Hope you get it sorted out. A few guys here have been traveling down a similar road. While you guys are sorting through your issues I'll be over here taking notes....so, hopefully, my build won't be as much of a PITA.


Advanced Member
Jul 28, 2014
Cincinnati, OH
Nice! Glad you got it figured out. It sounds great! What were the numbers and what's up with the fireball at the end?

Btw, I love the banner..."we make anything fast".

Sent from my Nexus 6 using Tapatalk


New Member
Mar 4, 2020
looks good. I have a convertible like it. I'm running a on3 on mine. Just can't get it to boost til 3rd gear.