[JLMounce]

https://www.streetmusclemag.com/news...o-big-engines/

Looks like FiTech is finally stepping into the big throttle body game with a 4500 flange offering.

Injectors sized to support up to 1600 hp on gas.

What's interesting is that unlike the Sniper 4500 competitor, this one is coming with interchangeable annular discharge rings and importantly, twin TPS to support progressive linkage for better street manners.

Could be a decent product for the guys running 500+ inches on the street that need the airflow and fuel flow of a larger flange throttle body.

No word on the the throttle body itself flows.

Looks like Jegs, Summit, Speedway etc. have them up for sale with an estimated 12/20 ship date. About $1600.00 without a fuel system.

[Scott65]

Looks pretty neat. I'm not grasping the dual tps concept though.

[JLMounce]

You'd have to monitor each bank of butterflies independently to fuel the bores properly if you were running a progressive linkage. A progressive style linkage can help tame a radical combination on the street compared to a straight linkage.

Sniper already had the Stealth 4500 option in it's roster. I don't know how much the two companies talk, if at all, but they have seemed to segment their offerings away from each other over the past couple years. Example would be if you want an EFI Tri-Power you have to go FiTech. Want an EFI Spreadbore, you have to go Holley Sniper.

Based on how this Nemisis is being marketed with the tunability of the annular discharge rings, multiple TPS sensors and the 3 bar map sensor, I believe that FiTech is trying to make this street friendly for high boost or big inch applications. The Sniper Stealth 4500 is a race system at heart. It's not really meant for street applications.

[Scott65]

Hopefully I'll catch some more in depth discussion on this. (Not that I need one, but I'm interested in learning)
I still can't fathom an actual need for 2 tps sensors, at least for my traditional understanding of progressive linkage. Are the injectors under the throttle blades? My dominator throttle body with progressive linkage works just fine with one tps sensor?

[62posbonny]

My understanding is the dual TPS are there to allow it to be configured as either a progressive linkage between the front and rear butterflies or a synchronized linkage opening them at the same rate and time. Synchronized would be very snappy but progressive could tame the throttle rate allowing for better street manners.

[JLMounce]

It may also be needed with the interchangeable discharge rings.

[adynes]

Only reason to have two tps sensors is to fool-proof the tune setup. One would work just fine, so long as the user doesn't forget to properly configure in the tune when making linkage rate changes. One less thing for the customer to screw up.

[er455]

What size injectors are they using i?

[JLMounce]

I haven't seen any literature on injector sizing or quantity. If we make some assumptions that like the 1200PA model it will utilize 8 injectors, then sizing to achieve 1600hp capability would need to be around 110 lb/hr. Those injectors wouldn't necessarily support 1600hp in a boosted application though. You'd need some more headroom.

[Formulajones]

The holleys we use with 8 injectors are rated to 1250hp with 100 lbs injectors as per Holley literature but in reality it's enough fuel flow for 1450hp.
They always rate these things a bit conservative with a very low duty cycle.

But I agree to get up in the 1600hp range you'll need a minimum of 8 110 pounders. I'd hope it at least has that for the 1600hp claim. I'd bet they probably have more injector than they need for that HP. 120-130 lbs. per hour would be my guess.

[JLMounce]

That would be my guess as well, somewhere around the 130lb/hr rate.