installed 2 engine tech heads 1 13.5 1 14.1 rpm lower now

[lightening800]

as it says me and deaner installed arts heads on our xps and now we find that the peak power of the sled is now at 78-7900rpm instead of 8200. now fron experience larger squish bands and higher compression ratios usually slow down motors but didnt think it did this to the 800. it isnt a bad thing because i had to add weight to the pins to find the sweet spot before the rpm started to drop and it pulls like hell there, if it want to rev at 7800 and make power there so be it the engine will just last longer.lol. and if your going to ask all kind of questions how i know this here are some of the tests we did to determin this, we swapped ecu did not change, swapped primary clutches and deaner is running the 413 ramps and would not go above 7900, clickered up lost rpm and speed, tried stock exhaust no change, tried different primary springs same 7900 hits wall, only reason i come to this conclusion is i tried to pull alll the weight out of the pins and it still would not rev over 7900 and would start the pipe ringing sound, so i said f it and and started weighting it up after a couple of tries it took about 2 grams in each pin and then the rpm started to slightly drop 50 rpm, and at 7800ish it pulls real hard no bull, so this is where it stays. also it has all stock clutching except heavier pins.

 

[fatguy1]

With a stock set-up and MBRP can my peak HP on the Dyno was at 8100 rpm.
With a stock set-up and HPS can my peak HP on the dyno was at 8200 rpm.
With Art's head 13.5:1 and a MBRP can my peak HP on the dyno was at 8000rpm.

 

[deaner]

The weird thing was..........no matter what we did, we could not get them to pull over 8000! I can see peak hp being lower with the head, but shouldnt it still pull higher rpms if you clicker up or drop weight? Even if its out of the engine's peak hp? It was the strangest thing today. No matter what we did, we couldnt get the sleds to pull past 8000. Changed clickers, primary spring, ramps, gearing, exhaust, ecm.......... 8000 it would hit a wall. Clicker 1 it would pull HARD at 8000rpm. Clicker 5 it would feel like a dog at 8000rpm! Im no tuner by any means.........but I dont get it

 

[GoldenRider1]

How come 2 different comp. ratios for the same sled? What elevation are you riding at? This is interesting to me because by all other reasoning right now my sled has too much pin weight in it, yet I love how it feels, I just can't get rpm out of it under load (in the deep stuff) so if my peak hp or power band were lower this could help my cause.

nate

 

[LRD]

I explained in detail on doo talk why this happened.

http://www.dootalk.com/forums/index.php?showtopic=298169&st=0#entry2249059

Good Luck

 

[GoldenRider1]

I explained in detail on doo talk why this happened.

http://www.dootalk.com/forums/index.php?showtopic=298169&st=0#entry2249059

Good Luck

Holy **** dude you are smart.

nate

 

[lightening800]

deaner talked to art this morn. and said this is totally normal, my rpm will be a little bit lower because i have my timing a bit higher than he does, so all we have to do is clutch for the NEW rpm spot. there are 2 different sleds with 2 different cr heads.

 

[Steelhead Slayer]

I guess a little too much HEAD can take it out of you....