Right back at ya.

 

I was talking about both of us for the educated guess clemson guy. As far as the dyno comment, show me the dyno sheets. Put your money where your mouth is or close it.

 

Clemson725, what experience, dyno, etc., would lead you to believe that 50hp is not unreasonable with these mods? From what I hear the heads on the stock motor are too restrictive to allow this increase. I'd like to talk to you about what other mods would net me 50hp. Naturally motivated, of course. R/T heads, M1 intake, 52mm TB etc.?????

Or should I just put the twin screw on?

 

If you twin turbo charge it, I'd have to say that'd be kick ***. I'm under the impression that many people judge horsepower increases by manufacturer claims. I went to college with a boy years ago that had a 1994 model z71. he claimed he had a 50hp increase because he had a k&n filter (advertised at 15hp), cat back exhaust (advertised at 15hp), hypertech (advertised at 20hp). Numbers dont add up like that. First of all the advertised numbers is the peak hp of the engine they tested that performed the best. More times than not that's a flywheel hp too, not a rear wheel. Average numbers would be more like 6hp/5hp/9hp instead of 15/15/30. Also think of it in a weight lifting analogy. If you flat bench press 200lbs, incline press 190lbs, decline press 225lbs, that doesnt mean you can bench press 615lbs. So back to the guy i went to college with. He probably gained 12-15hp MAYBE out of those 3 on a real rear wheel dyno. But what also is funny is the bigger tires he put on it. Somehow people forget to mention the things they do to their trucks that slow them down. To get a little more in depth with the original question though..........a computer chip upgrade tinkers with the air/fuel mixture. Some chip manufactuers recommend a cooler thermostat (which also tinkers with the A/F ratio) and a different air filter. Those untunable chips are preset for the majority of people that buy them which is basically a stock truck. So if you change filters, exhaust, intake, and get the chip, it is possible that you're pissing in the wind. This is a big factor with smaller engines such as in newer model sportbikes. An aftermarket exhaust can increase hp, but it can also decrease hp. It changes the A/F ratio and unless you get it dyno tuned to a custom fuel map, you might be going the wrong way on the hp curve. Im not sure how much different the RT heads would give you. I'm sure they wouldnt hurt though. They bumped the hp rating up 5hp when they first came out with the dakota RT, but the RT computer is different too so I would probably hunt for one of those if i went with the RT heads or get a programmer than you can fine tune. You are right about restrictive heads though. A bigger TB wouldnt help. If the heads cant get it out, it does no good to put it in. With larger ported heads you would want to consider bigger injectors which isnt a low cost item. Hey, thats the price you gotta pay for HP. If you port the heads or go aftermarket, and put a beefier cam in it, bigger injectors........then i wont be surprised to see the motor hit close to 300 at the crank.

 

Ok, I'll take that as valuable info. That's what I'm looking for on this site. I DO realize that there is a difference between HP at the crank and RWP. Such as my Yam R1 has 160 RWP. Any other valuable knowledge about the 98' 5.2 motor?

 

Well the choice is yours. You can listen to the bolt on gods on here and have the same truck as everybody else, or you can listen to someone that knows the value of a dollar.

 

I musta been reading 2 threads at once. Anyway yeah i have a 2005 R1. So you know what i'm talking about. I had a 5.9 liter in the truck i sold last month. I didnt do anything to it performance wise because lets face it, a 5000lb truck isnt going to be terribly fast unless you really want to pour the money in it. I put true dual flowmaster exhaust with no cats. Yes i said true dual and yes i know it can kill bottom end torque. I can tell you my reasoning behind it to clear up any issues. I had catback exhaust put on it in the form of flowmaster with 2 outlets. It really bugged me having 2 pipes out the back without it being true duals. As luck would have it my catalytic converter started to rattle so i cut it off and ran true duals. Eventually i got tired of the glass pack sounding pop when pulling in 2nd gear so i cut the tailpipes off. It was extremely loud but sounded extremely good. Anyway I noticed very little low end loss and no top end gain. The other thing i changed was the air filter. I put a K&N in it because i had a tendency to go down a lot of gravel and dirt roads and got tired of buying a new filter every couple of months. The 5.9 and the 5.2 arent really that different except for the small displacement difference. Performance wise the biggest gain and/or downfall i ever saw wasnt motor related. It was tire related. A lighter wheel/tire combo really made a huge difference in the peppiness of the truck. Maybe a lower gear would help. There was one other thing i did to my truck when i had it. That was put a 180 degree thermostat in it when i rebuilt the motor at 192,000 miles. No more engine pinging after i did that. I'm sure teh 5.2 is like the 5.9 in this respect since it has the same cylinder heads, but my heads were cracked when i went to rebuild. I found another set off a motor and they too were cracked. The 3rd set i found were off a motor with only 26,000 miles on it and they too were cracked. I eventually got a reman. set and put the cooler thermostat in there. The stock one is a 195degree.

 

Thing is..... going back to my ORIGINAL post, with let's say 270hp (your "conservative" figure at the flywheel). AND 4.10 limited slip gears, transgo shiftkit (putting this 270hp to the ground effectively) the HEMI x-cabs that are screwing with me shouldn't be a problem (in my 500 lb. lighter truck).

 

I put a 160 thermo in. I never had the pinging problem, but as soon as I bought the truck, I knew I was going to hotrod it (to some extent), so I put in the billet plenum from apsprecision.com. I had originally planned on s/c'ing it, so the billet plenum was the logical choice. I'm just putting off the supercharger and doing other mods that will complement it when I finally put it on, but I can see that it's coming to that.

 

Not sure. I've never ridden in one of those hemi trucks. They are rated at 345 with more torque than the 5.2 liter. Its really up to that torque number. Remember HP is calculated from torque and RPM. You might win though. You wont be embarrassed by it i wouldnt think. I highly recommend transmission upgrades if you're gonna be on the throttle that much. Nothing feels better than a crisp shifting, non slipping auto. I had mine rebuilt with a mild shift kit and a 24,000lb gross transmission cooler on it. It shifted a lot firmer, but wasnt clunky. It ran cool too which is a plus.