[Shotimes] How to get 300HP from your 3.0L SHO engine

[Don Donelson]

having built several motors like this ..I would agree with the numbers and the price .. but u can also shave heads for higher compression ... you can go to over size SI race valves ... and your right .. there are other tricks you can do too .. to make more.

I think 300 HP ... or low 300 HP is the maxium range these Yamaha motors can make .. with ALL The mods( naturally aspirated that is).

And for a track car like my SR 72 ... as much as I would like to get a s/c with say 6 psi .. max .... for durabilty .... I wont .. for I know I wouldnt keep the psi at 6 ! 

dond with a few mods

Sr 72 2800 pds
3.2 motor
ported and polished heads
.40 cams
SI race valves
BBB
extrude honed intake runners 
69 TB
port matched intake
port matched exhaust
adj sprokets
80 Pro flow w/ CAI
off road Y pipe and walker to 1  3" flow master
UDP
phenolic spacers
no/ac

---------- Original Message ----------------------------------
From: cmichaelo@optonline.net
Date:  Thu, 21 Oct 2004 11:47:45 -0400

>OK this is always fun.  How much HP do we get from each mod in a 3.0L engine? (This of course precludes adding displacement....:)
>
>What so fun about this is that it quite easy to increase the HP of this engine without affecting the cars usefulness as a daily driver and also without taking an equity loan on your house. You can probably do the below modifications for ~$5000 + labor.
>
>The HP numbers below are estimated based on the assumption that all modifications are initially installed in the car (thus producing 300HP). Then I take one modification away and "estimate" the HP drop.
>
>                                               Subtotal
>Base setup:        220HP
>                                                   220HP
>Rotating mass (external):
>UDP:                     5HP
>8lbs flywheel          2HP
>                                                   227HP
>Exhaust:
>HiFlow Y-pipe:       10HP
>2 1/2" catback:        5HP
>                                                   242HP
>Intake:
>77mmMAF + CAI +
>69mmTB:              12HP            
>BBB + EH +
>porting:                 15HP
>+20 CAMs:           15HP
>                                                   284HP
>Electronics:
>WideBand HEGO +
>Tweecer:               15HP
>                                                   299HP
>Lubrication:
>Amsoil 5W30:         1HP
>                                                   300HP
>
>There are other things one can do, but that will affect the usability of the car as a family sedan, namely:
>
>Intake:
>+40 CAMs            10HP (assuming a +20 base)
>
>Rotating mass (internal):
>Forged crank +
>rods + pistons:     10HP
>                                                   320HP
>
>For a grand total of 320HP.
>
>And there are probably other tricks too, such as flipping the [forged] pistons 180deg, lowering friction of all turning parts by properly coating them, etc.
>
>What do you think the HP numbers should be???
>
>
>Michael
>94MTX,green,BOS+,Koni/Intrax,Baer,Corbeau
>SHO items for sale: http://hometown.aol.com/cmichaelo/for_sale.html
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