21.5lb or 24lb injectors for Riot Racing cams

[Rugbyfan]

Both the tuner I’m using and Riot Racing say 21.5lb injectors are adequate for a full bolt on s52 with street cams. Anyone ever have an issue with 21.5’s not being adequate? What whp can 21.5’s support?

[pbonsalb]

Maxed out, close to 300 rwhp. The S52 is very efficient, with a BSFC around 0.45. That works out to 47 rwhp per injector, times 6 is over 280 rwhp. That is just rough math. But if you are doing full bolt on mods and buying a tune, buy the injectirsthe tuner recommends. Maybe 24 lb. Full bolt on S52 have been around for 20 years and the tuners typically do use higher flow injectors.

[Rugbyfan]

I’ll be sticking with my 21.5’s. Thanks for the input

[lbennyboobool]

How much power are you expecting from the cam upgrade?

[Rugbyfan]

With the below mods on a 60k mile Obd-1 s52, I highly doubt over 245ish whp. Probably closer to 240

S52
-UUC lightweight fly
-Tms shorty headers>dual down pipes>x pipe>dual pipes> stromung (no cats)
-540 maf
-3.5in elbow
-riot racing 68mm TB
-m50 intake manifold
-riot racing cams
-resealed Vanos
-21.5 injectors
-93oct trm tune for the above

[pbonsalb]

With those mods and a good tune, maybe in the range of 260 rwhp SAE Dynojet.

[Rugbyfan]

I guess i’d rather be pleasantly surprised than dissapointed. Riot is 3 weeks delayed so I’ll have to wait and see.

[pbonsalb]

Let us know your dyno results. European car got 246 with Schricks and stock headers and stock midpipe. Super Street got 265 with Sunbelts. Otherwise the cars were modded like yours. You should be closer to the latter than the former.

[Rugbyfan]

Will do. Once the cams are in there is a dyno 40miles from me. Unfortunately I won’t be doing a before/after

[GG///M3]

I got 245whp out of my s50 without cams, but it did have full euro ss headers, euro ss x pipe, muffler, 24lb injectors, afe intake, 540 maf, and RK tunes tune.


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[1000hp]

Broke into the wrong goddamn rec room didn't you, you bastard?

Your 21.5s should be plenty.