Formula 357-SR1 Top Speed and REVs
 

Hello all! A friend of mine just bought a 1987 Formula 357-SR1 with twin 502 EFIs with TRS ODs. One motor turns at 5200 RPM and other only turns at 3500. No tell tale signs of major engine problems. Runs and idles smooth up to 3500, but maxes out there. It is running in the high 50s like this. 2 questions, what should be the top speed for this boat with this set up, and any ideas on what may be causing the limitation? He does not want to pull anything apart at this point as the former owner may take it back. The former owner stated low to mid 80s (which I personally doubt). Thanks!

My friends '86 does 80mph on the nose in cool air with little fuel. His has bravos with 26's, and it spins 5100 rpm. It takes 454's with 250 blowers to do that. So I would say his estimate is a bit high. It should still move out pretty good with the EFI's.

My 311 with 502 efis and Bravos runs a solid 70. I think your buddy is looking at 65-67, maybe a little less. I would check fuel pressure first on the weak engine, sounds like it is starving out at top end-really bad to run it like that BTW.

I would think if you can run high 50's with one motor at 3500 that you should look at the tach .... swap the grey wires on the tach's ....

I have a 84 F402 sr1 with 502 efi mags. At 4500 rpms runs 52 on gps. Running TRS with Bravo 1 22p 4 blade. Haven't tryed the 3 blade yet but was told should see low 60 high 50.

63 gps for me with 485 hp per side. TRS

My 357 ran 66mph with Kamma surface drives, and 475 hp per side at 5200 rpm, There is no way these boats will go anywhere near 80 without big power. I would also check the accuracy of the tach. I would think low 60's for that boat dialed in. The 357 is a sweet ride.

I was wrong on the props they are 28's.. I don't know what is considered big power but similar motor builds have made 625 - 650 on the dyno. Tachs are accurate and new. I believe bravos are faster than TRS ie they rob less horespower. I am not sure about the Kammas. The shame is that his boat was originally a Kamma boat but was converted sometime before he bought it.