Rays C5

After 3 month of having the heads I finally got them installed and dynoed. 5:30 sharp at 99 degrees in the shop I came back with 367.9 hp( and still climbing) and 343 torque at 6300 rpm.Thats 25 hp gain and 20 ftlb of torque from 3500 up. The kicker is a/f ratio started at 12.6 at 2600 rpm pull going down to 10.60!!!!! With 13 to 1 being the ratio to get to and I'm obviously very rich how much am I leaving in the table???Looking some one who has tuned on the dyno the same day and saw gains but any input I'd appreciate.BTW I dynoed stock low stock so these numbers maynot be very high to some but from where I started I'm happy. But back to the question, I'm sure there have been plenty of guys/gals that have before and after and I know they are only numbers for tuning purposes.

Rays C5

Come on guys I know there are some before and after gains on changing a/f ratio!!

Nate_Taufer

iTrader: (1)

graph?

nate

66deuce

iTrader: (1)

well,back when i was bolt on only i gained 10hp going from 11.9-1 to 12.8-1.i would think you would gain more plus you might benefit from playing with the timing a little bit.i think those are good numbers considering your baby cam, stall and an IRS.

Rays C5

Thanks deuce!! I'll look into adding a little more timing. Trying to squeeze 380 hp out of her. Sorry have no graph.

66deuce

iTrader: (1)

what heads are you running,or what did you have done to them?what's your CR?

NOSjohn

iTrader: (9)

Was wondering what heads as well...

Rays C5

Stock 98 heads with stock compression. Had them hand ported and unshrouded the valves.Based on the flow sheets ,stock they flowed .223intake now they flow 268 and increase of over 40 cfm which almost lines up with theory I've read before that for every increase of usable air flow that hp increases the same numericaly. This will be about right if I have 12 to 15 hp to gain from leaning it out.(dynoed a/f 10.60)fat. Is this possible????

66deuce

iTrader: (1)

i would think you could gain that from leaning it out.in my experience,autos don't like as much timing as M6s,so you probably won't gain much from advancing it too much over stock.but every motor has it's sweet spot.i gained some power in the lower range from bumping the timing a little bit below 4500.if you have tuning software,just do a lot of logging and trial and error to find out what works best.just curious,how big are your ports now?i had a set of 5.3s ported with the intent of removing as little material as possible.i ended up with 213cc int. and 79cc exh..small ports work better with smaller cams,IMO.(i have a TR220).

Rays C5

The porter port matched head to intake gasket but thats it.... otherwise stock.btw how did the tr220 work out for you???

66deuce

iTrader: (1)

it's a great little street cam.i was going to go bigger,but now i'm glad i picked it.has plenty of power down low,i don't go to the strip that often so i wanted good street manners.it really works good with my 3000 stall and heads.i think i have the tune just about dialed in,but am waiting to go to a dyno and put a wideband o2 on it.i ran it a couple of weeks ago and did a 12.60 at 110.55,with a shitty 1.96 short time,spinning thru the 1-2 shift.i need street slicks,but i'm afraid of breaking the rear end,lol.with slicks and my latest tune i think 12 teens are possible.

66deuce

iTrader: (1)

hey,what are the flow nos. of your heads,not just the peak nos.i bet it's real fun on the street with that little cam.

Rays C5

valve lift intake cfm exhaust cfm
.200 142 117
.300 193 154
.400 234 184
.500 260 205
.550 267 210.8
.600 268 215

Oh yeah, Pulls almost off idle and never backs down all the way to 6300rpms(still pulling but that is as far as I wound it up!!!! I started to go with a tr224/112 cam that I had excess to and prabably would have gain another 10 to 15 over this cam but I spent 2 to 3 months trying to dial in the ve tables and after all was said and done put the stock tables back in to get my gas mileage back....somewhat put a damper on getting deeply invovled with tuning this car.....have a z28(87) thats my toy also that I spent 3 years tuning!!!!