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69CamaroRacer
09-16-2005, 03:38 PM
I have a new 383 with about 150 miles on it. The engine has all the best goodies.. Ported AFR heads, 10.5-1, .560 lift cam on a 236* duration, 10.5-1 ext ext... Anyway I was hoping for somthing in the neighbor hood of 500 hp and I don't think that I have it... Now the question is how much power can be lost because of the engine being out of tune? The timing needs to be set the dist needs to be curved and the carb is just as it was out of the box.. I am waiting to get some miles on it before I can take it and have it dyno tuned. Also I have heard as the rings seat the engine will get stronger. What are your opinions... This is the first new engine I have had so I don't completely know what to expect.

ProdigyCustoms
09-16-2005, 04:07 PM
You could be 50hp off with timing and carb, unless it is REALLY off. But to be hinest with a 236 cam, you are probablt closer to 450hp ona perfect tune. You would probably need to see 246 or so to be near 500.

So assuming you are off 50 on your estimate, and 50 off on tune, does it feel like 400hp?

I like to set my timing at 36 to 38 at 3000, rap it to see if it advances, it should not, then see where it is at idle. 14 to 18 should be right, assuming 20 degrees in the advance. Then trying jetting it up 2 sizes until it feels like it slowed down, then back up. That is the quick easy, no rocket science, non plug god reading, back yard, way to do it. Then play with the timming moving it up towards 40. If the heads are real good, it should like 36.

This should get you very close. Then you can strat playing with accelerator pump cams, air bleeds, etc.

Lowend
09-16-2005, 04:40 PM
I have found as much as 250RWHP tuning on the dyno... its pretty huge.
I would expect your motor to be putting out 475-500HP in proper tune

yody
09-16-2005, 06:38 PM
I would expect about 430/475 Hp/tq, We built a similar combo but with a little bigger cam and Trickflow 195 heads and a bigger solid flat tappet and it made about 340 horse and 480 torque at the rear wheels in a 80 camaro. Putting the car on the dyno with a wideband O2 is really the best way to tune it, at the track can work very well too, but I always like to know the motor is pretty close to the way it should be before I flog it at the track. Basically eveyrhting Frank said was right on, that cam is fairly small for that motor. Your going to have excellent street manners and a lot of torque when you get it all right. ITs kind of a waste of time to really figure anything before you get it all worked out, get that timing 100% and then post back, what kind of cam is it? can you change the valve lash, can you give more detials on how it runs?

69CamaroRacer
09-17-2005, 04:23 AM
Yody,

Just to answer your questions it is a comp cams XE series hydrolic roller, it is not a solid so that valve lash is not really adjustable. As for how it runs it starts up and runs strong but like I said the timing is way off and I can hear it pinging under heavy load so I know that it is not 100%. Also I am a little concerned about the carb it is a Holley 750 HP series while adjusting the screws on the primary side I turned the driver side screw all the way in and the car did not die. I thought that if I did this it would surly stall. When you preform this same action on the passanger side screw the car will stall out. I turned them all the way in and than back out 1.5 turns just to try to get a base. The car is still running very very rich. Gas milage has been around 8-10 mpg.

WELTERRACER
09-17-2005, 05:54 AM
my buddy has a 383 in his 93 camaro LT1.. it has AFR HEADS, 1 3/4 headers, and cam similar to yours and it is making 411hp and 419ftlbs of torque at the wheels.. granted he is running more compression than you.. 11.8-1..

i would say frank is right. under perfect tune you should be at around 450hp with OPEN exhaust!

Set your timing at 36 degrees total at 3000, if it pigs back it off a few degrees, make sure you have good fuel in it.. atleast 92 octain.. Your jetting might be a few sizes too large!

yody
09-17-2005, 09:43 AM
That is normal on the carb you have a four corner idle so 2 of them would have to be seated for it to die. My carb runs best with barely and idle transfer slot showing, they should look "square" when you pull the carb off and turn it upside down and look at the little slots that the throttle blades are covering up. My car runs best with the idle mixture screws only 3/4 of the way out, everyone tells you something differnent, but my engine starts doing weird things once you screw them out more than 1 turn. Also make sure you aren't running your PV's open. They should be a few sizes smaller than you vacuum at idle. What kind of gearing do you have, does it ping in high gear? if ti does you might consider the stiff spring and one light. Before you start getting all worked up, get the correct bushings/springs in the dist. I like about 15 initial, 36 total on a setup like yours, so the 21 degree bushing should work, I also like to use the blue/light silver springs to get the advance to limit to about 28-3000rpms. Then set the idle mixture screws to about 3/4 turn and set the transfer slots, and check your vacuum and powervalves, then check back with us, also put the jetting back to stock on the carb

MuscleRodz
09-17-2005, 10:48 AM
Did you read one of the last G-28 articles in PHR? That $8K 400+ hp engine Jonny put in the Camaro dyno'd like 177hp with the stock junk exhaust right out of the box. There is a lot that can be left on the table in drive train losses, poor exhaust, inadequate tuning, and on and on.

Mike

ProdigyCustoms
09-17-2005, 01:22 PM
Yeah, your idling off the jet, not the idle circuit. Take a turn out of the throttle blades and close them more, then set the mixture screw at 1 1/2 turns. If it will not get on the idle circuit, you may need to drill some 1/8 holes in the primary throttle blades to give it more air, so you can close the blades. This is real common on Holley's on high perf motors.

Start with the carb idle, reverse time it, and take it from there.

streetk14
09-17-2005, 03:07 PM
I'd say start with the timing and go from there. Set the timing curve so all mechanical advance is in by 3000 rpm. I'd say 35 degrees total is a good number with those heads. Improper timing will have a huge affect on power. What cam are you running? Is the 282 or the 288? If it's the 288 (236/242), you should be right at 500 hp & 500 lbs of torque when properly tuned. What gearing and transmission are in the car? If an auto, what torque converter are you running? What do you have for headers and exhaust? Is your fuel system able to keep up with the new motor? All of these things can hurt the performance of an otherwise strong engine. Also, if you can hear it pinging under load, you probably shouldn't be driving it. Get the timing in check before you damage anything. Good luck,
Andy

69CamaroRacer
09-18-2005, 11:54 AM
Streetk14,

The cam is the magnum 280hr (http://www.compcams.com/Technical/Search/CamDetails.asp?PartNumber=08-450-8) As for the trans it is a turbo 350 with a 3200 coan converter. The diff is a 12 bolt with 3.55 gears and the exhaust is a custom 3in with x-pipe set up and the headders are 1 3/4 headdmans. Everything is brand new. The ignition is msd 6al ,msd pro billet 55551 no tuned byth 8.5 msd wires. The combo will be dyno tuned by the shop who did the motor but I still need to get some miles on the motor before I can do that... Right now I have 2 issues to work out... the fuel pump failed so I ordered another edelbrock mech pump from jegs and I have a mini starter and for some reason the bendix is hung up on the flywheel so I am gonna have to fix thoes problems before I can do any tuning... anyway thanks for the advise ...

69CamaroRacer
09-18-2005, 12:07 PM
here is the combo
69 Camaro RS, 383ci,10.5-1 AFR 195's ported,(flow 278in 220 ex) Comp 286HR, 4340 forged Crank & Rods, JE Pistons, Flowed and Balanced RPM Airgap, Holley 750 HP carb, 350 turbo w/ shift kit, 3000 Neil Chance converter, caltracs,12bolt 355 eaton posi

streetk14
09-18-2005, 08:35 PM
With that cam you might be looking at 475-480 hp at the flywheel in proper tune. I have that same ignition system in my car. That distributor has a very slow advance curve out of the box. I would swap out the bushings to limit the total mechanical advance (I use the black ones but I also have less cubic inches/more cam duration) and change to lighter springs. The advance curves are included in the instructions of the distributor. I think the stock curve doesn't reach max advance till 6000 rpm or so; not good for performance. Let us know how it goes,
Andy

yody
09-18-2005, 09:12 PM
Ditch the edeljunk fuel pump and put a carter 172GPH Nascar mechanical pump on it, they are about $75 from summit. They will require a few different AN adapters to get them to work(have 10AN inlet) but work Great. Don't worry about breaking in the engine, as soon as my car was drivable I started taking it out doing high rpm blasts, my motor has about 50 miles on it, and i have taken it to 6500rpms probably about 20 times already. No smoke, plugs look perfect, with todays ring design and boring techniques the break in procedure isn't needed except for cam break in on flat tappets. IF something is going to break it will. Usually the rings break in when turning the motor over to adjust the valves, or cranking with the starter. Go ahead, recruve that dist. Leave the box stock jets in the carb, and take it to the chassis dyno. Just make sure you are getting full throttle from the carb(while flooring the gas pedal, make sure the throttle is opening 100%. Make sure your tranny has the correct amount of fluid, and make sure you fuel pressure is correct and doesn't drop under load. Make sure the fuel pressure is right and it isn't leaking out of the boosters while running, although with that mechanical pump it shouldn't be a problem. That pump probably isn't providing enough gas for your motor. What are they like 80 GPH? Also besides saying its running rich you haven't really mentioned how it runs? SO whats the deal, any ideas or responses to the questions statements anyones made?

69CamaroRacer
09-18-2005, 09:26 PM
Yody,

The fuel pump is a 110 and it is rated for 550 hp. The engine runs good sounds great but just doesn't seem to have the power I was hopping for but I think that it might be because I have a few things holding me back. The fist is i need to have the linkage to the trans adjusted so that I can pull it down into first and hold it there .. Right now I can pull it down into second but not first. I know that the trans is ok because if I stomp it from a dead stop it will light em up for a country mile but it shifts from first so quickly on its own I need the ability to hold it there. The second problem is my tack is not hooked up so I have no Idea how many rpms that it is running at and if has been pinging bad under a load... Tomarrow if I get my parts in the mail from jegs I will fix the fuel pump and then I have to see what happened to the starter.. I bought the expensive mini starter and I might just end up going with the stock auto zone cheapy starter if I can't make this mini work... hey $35 vs $250. Right now I can;t do any tuning until I get thoes two things fixed. Thanks for the advice...

yody
09-18-2005, 09:45 PM
sounds like you need to shim the starter differently not a new one. Also the pinging could be from a lot of different thing. 110 will get you by but I would not even on a good day consider 110GPH sufficient for 550hp, but it will probably work for you.