650s and 680s are the same injector (AFAIK). You won't make enough power to run out of injector with 650s, but get 750s if that makes you feel better.

You are using methanol/water injection in an attempt to improve power over pump fuel. Use of methanol reduces injector duty, and therefore reduces the required injector capacity.

FYI

 

Thanks for the reply.
BTW local premium pump gas is "supposed" to be 95 RON. Maybe 93 RON in fact??
Any thoughts on the Piper cam kit suggested for use with the FP EvoGREEN turbo?

 

95 RON would be roughly the U.S. equivalent of 90-91 octane - not especially suited toward making power.

As far as the Piper cams, I recall one convincing A/B dyno test of Piper Road cams vs. HKS 272s that did not fare well for the Pipers. I don't know why that was the case, but since then, I've steered clear. For road racing with that turbo, ported head, etc., I would use something along the line of Revolvers - enough lift to take advantage of the improved ports, but not so much effective duration such as to soften the response of the moderately sized turbo.

 

Humm, thanks for the heads-up. I'll do a search of the Piper/HKS cam test.
Unfortunately Revolvers are not available. Buschur has a new alternative that I'll research.
Info and suggestions are important to me since a 4wd dyno isn't available for testing yet.

Thanks again.

 

upgrading the injectors even with stock turbo will give solid torque gains if tuned properly. This has been proven several times. However, anything over 770cc injectors don't seem to get along as well with the stock ECU/MAS. AEM EMS FTW.