Will it take anymore? Am I maxed out?

[stroker1]

Just wondering what you guys think. I was hoping I could make it to the 6.50s but not having any luck so far. And other than going to a T-brake I'm beginning to wonder what will speed it up.

Combo is: S-10 long bed with caltracs, 8 pt. cage, aluminum dash, 1 racing seat, no fenderwells, lexan back glass, fuel cell, 9" rear end w/4.56 gears, PG with 1.82 first gear, 383 sbc Performer RPM heads (170 runner), 13.3:1 compression, 6" rods, internally balanced, cam is .640"/.604" 256/268 @.050" 102 ICL and 106 LSA solid roller. 8" converter footbraking to 3000, Hussler fenderwell headers 2" tubes with turnouts, tall single plane manifold, Holley 750 double pumper w/Proform mainbody and baseplate, electric water pump, 28 x 10.5 slick, front trick springs, SUCKWOOD 90/10 front shocks, Centerline Convo Pro wheels 3.5" front-10" rear, and 1 stage plate shot NOS Cheater kit.

Here's the deal. Locked timing out at 32 deg. I've jetted it 63N/71F and went 1.51 60ft 6.60 ET at 106 mph for best ever. And have gone 6.666, 6.666, 6.696, 6.71, all on the same jetting with 60ft right around 1.55-1.57 usually.

Then went to square jetting 63N/63F and went 1.55-1.57 60ft. and 6.65-6.71 ET at 106 MPH.

Then went to 71N/73F and pulled 1 more degree timing. This Saturday at Fayetteville it went 1.53 60ft. 6.63 ET and 107 MPH.

It don't seem to respond to the change in jetting and the 60ft. does seem to suck! Am I doing all it will do with the little heads and no T-brake?

[mytmouz]

Nah, there has got to be a problem somewhere, as my buddy's 68 camaro with a pump gas 383 goes 6:90's on motor. What type of tall single plane is it? I had a problem with a Weiand once choking my engine. Is that a typo on the cam lift? That's a pretty big jump, also the LSA is pretty tight to be on spray, even with a small shot. Also, that's a pretty small runner for the cid they are on. Hopefully someone else will chime in...

[John_Heard]

What solenoids do you have on it? You might be reaching the flow potential of the cheater solenoids? Sorry I don't recall what those will move, maybe someone else here will remember?

[stroker1]

Nah, there has got to be a problem somewhere, as my buddy's 68 camaro with a pump gas 383 goes 6:90's on motor. What type of tall single plane is it? I had a problem with a Weiand once choking my engine. Is that a typo on the cam lift? That's a pretty big jump, also the LSA is pretty tight to be on spray, even with a small shot. Also, that's a pretty small runner for the cid they are on. Hopefully someone else will chime in...

It's a 1.6 rocker on the intake and 1.5 rocker on the exhaust. That's what makes the best power for my cam on motor. A Profesional Products Hurricane intake ported heavily and smooted to get out all the casting flash. Yeah, it was built to run barefooted but I decided to spray it a little bit. I thought it would pick up more than 2-2.5 tenths. It goes 6.90s on motor in bad weather and has been 6.83 on motor.

What solenoids do you have on it? You might be reaching the flow potential of the cheater solenoids? Sorry I don't recall what those will move, maybe someone else here will remember?

The cheater will go to 250, and I've only tried a 150 (per NOS) then square jetted the 150, then almost square jetted the 180 shot. Didn't do nothing but gain 1 mpg from 150 squared to 180 squared.

What I'm wondering is, have a reached the limits of my heads? And is my 60ft. as low as I'm going to get it without a T-brake or restalling the converter? I really like the MPH that the converter is doing.

[Scott Coxwell]

Just a quick post,,, My first thougts are if you've increased HP and plugs still read good then your probably blowing thru the converter or spinning the tires more no. One of very first hot rod motors was a 383 and I believe to this day it is the very best one I've owned!! Not much help but there you go...

[waterdog]

Could you have a clogged nos filter or screen? With a 150 shot we used to see about 8/10.Walt

[rontoomanyprojects]

At 3000' elevation a 150 shot I picked up 1.2 seconds. Went from 12.82 to 11.60.

[stroker1]

I know the faster you run on motor N/A usually the less you will gain with n2o. I ran a 6.63 saturday in the 1/8th and had lifted and still went 11.21 in the 1/4 all the way off the gas.

It runs pretty good N/A for what it is, but I was just concerned it was reaching the point it wouldn't flow anymore with the same heads and cam. Seems like if it had plenty left then it would pick up more than 2 or 2.5 tenths on the giggle gas.

[supernova]

I think the 170 cc heads might be it.
I ran a 385 motor with 200+ cc TFS heads ported on 200 shot NOS system, 4.30 gears, PG with 1.76, 3200 lbs 68 Camaro, 10.5 tire, with a smaller cam then your, 11.5-1 comp. and ran a 6.19 in the 1/8 mi.

Your cam isn't the best choice for NOS with that small if a head. I can't believe your getting it to run that good.

I would think about a head change ( Dart 210 cc) and call comp cams and ask for the cam help line, talk to Mike if you can. Get the specs of the cam that will work for your new combo.

You could back off on the launch stall and flash the converter harder and see if the harder hit moves it faster. Say 2000-2200 rpm's to start with. Just a though.

My 2 cents

[animal]

The cheater plate jetting is wayyyyyyy fat , maybe go 72n 55f @ 5.5 fp , pull 10 degrees from total spark lead , pull plugs & tune from there , 8s should be fine.
Remmember , lean is better than fat.......... too fat @ you'll be pullin the slugs out , maybe the 1/8th has given you some slack , run the 1/4s on that tune i'd be worried about lifted lands.
The cheater noids are good for around a 250 hit on the nitrous & a 400 hit on the fuel.

Seems to me the cam is too big for the motor , bleeding off too much compression (dynamic) , the tight LSA (106) is'nt helping much regards pumping losses , nitrous motors need to open the ex valve sooner than when running NA , so a wider LSA might help , also that 106 LSa is pumping a fair bit of the nitrous charge straight out the ex valves on overlap , a cam ground on a 112/120 LSA would be a better choice (lsa being the resultant factor)

Nitrous motors fair better with longer duration/higher lift ex lobes , seems some of your problem lies with the intake being 1.6 RR & the ex being 1.5 rr , maybe switch em over.



Great site this , have been looking for some time so decided to join up , thanks.

[DL]

let us know about the 73 n 55 f at 5.5 f psi i think im running my tune ups to fat as well ive been squarring mine at 6 psi big shot solenoids with a cold fusion plate

[stroker1]

UPDATE: I just went to Fayetteville to Grudge Wars Saturday. Got rained out, but got in 2 shake down runs. Went 6.54 @ 108 mph and 6.53 @ 108 mph. This is a big improvement. I went to 1.6 rockers intake and exhaust and also 7/16" studs. Motor sounds bigger and deeper. Still ran a 71N/73F tune up and it was surging due to a fuel pump going bad. So I think it's got a little more in the little 170 runner heads.

Yeah fellas, I know I don't have a nitrous cam and could use some bigger heads, but I'm more pleased with it now. I never thought it would go a 6.50 with the current combo.

[sunsation540]

i have 2 diffrent foggers one is a modified kit from steve johnson and the other one is a sportsman fogger the fuel sol are good to 250 each and the nos sol are flat at 175-200 each i have used the sportsman kit from 125-300 and it quits gaining over a 26 nos jet and i don't use MR ET i use scales to weigh the bottle no weight loss over a 26 jet have gone to a 32 again no gain for what it's worth up grade the sol.. P.S. they are pig rich on the nos settings you could gain more from pulling fuel than upping the NOS

[stroker1]

Another update....Last night it went 6.36 and 6.34 at 107 mph. So I guess the answer to the question is (No it was not maxed out.) Man this little head motor ain't supposed to run like that. I omitted the red pump for the nitrous and branched of the other side of the regulator from the blue pump that was running the motor. I know that was asking for trouble but I had to try it (my FPSS should have shut it down if the fuel pressure on the blue would have dropped. I left the fuel pressure at 7.5 for the carb and went up to 7.5 for the nitrous. I didn't have the right fuel jet to go down so I went up on the nitrous jet to try and keep the mixture more in line. Ended up jetted 73N/71F at 7.5 psi fuel and 1000 psi bottle pressure. Probably a little rich but at least it wasn't surging. Man I'm happy with it. And on 'ol Edelbrock RPM heads too!

[rustbucket]

good job!