Patrick,
What injectors would you recommend with this turbo on a 231 inch motor?
On paper, the Billet 67HPQ turbo is rated to support 920 fwhp.
75# Delphi injectors will safely support 900 flywheel hp with the right pump.
79# SMP disc injectors will safely support 948 flywheel hp with the right pump.
80# Siemens pencil injectors will safely support 960 flywheel hp with the right pump.
84# Delphi injectors will safely support 1008 flywheel hp with the right pump.
Honestly, it really depends on which EMS system is used. (Stock ECM/ Stock MAF with custom chip setup, Stock ECM with translator and custom chip, Stock ECM with SD TT chip, Big Stuff 3 or XFI) Everyone's idea of street ability is different. IMO, you want to run the smallest injector that can safely support your hp goal, without having to run the injectors close to 100% duty cycle. Especially if street ability is a concern. Meaning, the larger you go injector size, the more intense the chip program and tweaking that will be needed in order to get perfect street manners. 75# and larger injectors flow a lot of fuel and because of this, the fuel tables are more labor intense.
If you know you want to make 600-700 flywheel hp and you have your fuel pump/pumps squared away, then the 75# low Z or 80# high Z injectors would work nicely and not come close to being maxed out duty cycle wise. Just look at what Bent6 said about his combination and his injector duty cycles. Personally, I like the 60# Siemens Mototron injectors and would feel comfortable running them on a stock built motor with a good fuel pump, race gas, a TT chip and high boost. I have also heard good things about Eric's new SD chip and the 80# high Z injectors as well.
Very good post everyone.
I still think it's possible, but definitely not typical of the general population. For sure, something is amiss to blow a head gasket at only 18psi while running decent octane. Without having any datalogs to compare boost readings with, I would definitely be checking those hoses too. I would hate to have a repeat headgasket issue. Also, make sure you do your best to clean your oil system as much as possible. I would even go so far as to remove the pan and clean the oil pickup screen of any debris. Flush all the oil lines, especially if you have the external oil cooler hooked up and or oil filter relocation kit installed. Residual coolant in the oil is bad, especially on a dbb turbo that requires very little oil for lubrication. If you can imagine what water in the oil will do to a bearing that's spinning at 100k + rpms under extreme loads. And it doesn't take much trash in the oil system to clog the oil passages in a dbb cartridge. And a blown head gasket, depending on which way the gasket blew, (into the valley or outside the block) can spread a lot of debris into your oil system. A little time and effort here, spent cleaning and flushing, will save you big time in the long run.
Just my O2's worth.
Patrick
