Before I went with a forged/stroked motor in the Hemi Ram it was making 23 rwhp per lb of boost. In stock trim it made 260 rwhp and at 7PSI it was at 423 rwhp.

As stated above if I am currently making 250 rwhp and I add 15 lbs of boost at say 20 hp per lb I will have a total of 550 (250 + 300) rwhp. But if I start at say 350 rwhp it NA form and add the same 15 PSI I would be at 650 rwhp.


I think it is crying for boost and maybe that is all it really needs. I will have to oblige the engine and slap the turbo on it to see.

 

Just doit. Boost rules, everything else is second.

 

Hmmm. I dont agree at all. Take a turbo camshaft and with the exhaust valve events going on you will never make good power on a NA motor. Not close like a huge giant NA cam would. Now put pressure to that turbo cam and watch as the TQ becomes so great that it makes HP. The only reason people make HP is because they make TQ. Its a simple Dyno formula.

And if you want to take a motor and make max HP out of it then add boost to it, you now have a motor that wont make good power under a boosted application. Been there and done that. You cant have boost with compression. You cant have boost with tons of timing. So you have to pick what route makes more power. Usually boost, then timing, then compression in that order is a good rule of thumb. Unless you want to act like a baller and run C16 race fuel all day, then maybe you can change it around, but we are not talking about that.

Rick

 

why wouldnt a motor that is designed to make a solid amount of NA power just at low cr work well with boost? you mention cam..the ls6 cam that is very popular choice works very well in boost and it was intended to be a NA cam. ive seen and im sure you have seen plenty of setups over on tech making 4xx with large cubes NA. those are the boys making close to 4 digits or in the 4 digit mark for power. yes they have more money into their setups but they also produce the numbers and have the better ETs for most part. if the motor can withstand the pressure then higher cr wil make power. look at alcohal [sp] motors they arent no 8.1 cr they are much higher and run higher psi's but that isnt an ls1 but just a statement. 8.7-9.2 seems to be a nice happy medium for the ls series of motors. 9.0 being average isnt all that much of a dog. its not the strongest compared to other setups but 9.0 can still be made strong. and the HP difference between a 9.0 and 10. motor is only going to be roughly 30 hp NA. im also aware the hp is an after effect of torque. and looking for running race fuel, yes it allows for more power at a higher cost and safer. if you shoot high for high numbers expect to pay for the supporting mods.

shoot for a power goal and build the motor around that. if you only want 5-600 rwhp you can use a 5.3 for that build.. if you want around 800 a nice 6.0 is in works you want 4 digits a 4xx cubed motor is what you use. now there are exceptions to rules and using the smaller cube'd motors. but in the end make your combo as effeicent as possible then add boost to it and youll see the numbers you want. if you build it poorly dont be upset when you see less then stellar numbers

 

I understand that building a FI motor will make less power off boost then an all NA motor but I did not think my power would be that low. The day I dynoed there was a 5.3L Tahoe with just an exhaust, CAI(K&N) and tune and it put down 245 hp and 260 tq. My numbers were only 5 hp and 20 tq more with 80 ci more.

Below is a link to a FI motor with similar cr(9.2 vs 8.7) and cam(224/230 .609/.604 113LSA +2 vs 224/231 .595/.595 114LSA) and it put down some very respectable numbers. I would love to have something close to that before I put the turbo on. https://ls1tech.com/forums/showthread.php?t=857261

 

exactly but dont forget he has the mods to go along with the power goals. make most NA then add boost. patrick G did this exact thing. his little 347 on boost will be a beast

 

What mods are you talking about?

 

heavily ported heads, ported fast90/90, im not sure if he has EWP and UDP

 

See, in your last paragraph lies the correct term. Efficientcy. Does not mean the motor should be efficient off boost, but only under the case it is being truley used for.

I do not disagree that his motor does sound alittle fishy with the numbers, but I would just not go around being mad about it. Thats the point I am making.

Marks truck on 12psi right now is a 438 making about 750hp. I guess it would be making only about 375-400 all motor then? So that would be about .9hp per CID then. And on boost its making about 1.7 HP per CID now. So I am not sure if I would follow that too well since too many factors go into a turbo motors design. Like TQ and HP could be totally different in every setup. As you come into the Turbos efficientcy window, it only gets better, not worse.

R

 

Again, you cant look at others. You need to look at yours. I have seen all motor setups, all parts being the same, drop 80hp from a full point of compression. But, you could also have something else wrong. The hard part about trying to make power with a low compression motor and a cam is the timing. First off, a camshaft will only take timing to the point where you come off the camshaft. So since you dont have enough compression to make the motor knock, then you just wind up going with too much and doing nothing. And even if you find the sweet spot, there is still not enough DCR to make anything worth making. So too many factors come into play.

Rick