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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
Well boys and girls the time has come. Spent 6 hours at the dyno and made 15 pulls. Right out of the box she made 474 torque @4300 and 446 hp at 5400. Torque @ 4000 rmp all the way to 5100 rpm was from 479 to 456. That was at 40* timing with 71 and 80 jets. From there we went to 35 on timing and changed some jetting. It didnt like it. We chased the numbers all around all day ending back with 40 deg on timing and 71 and 83 jets. All in all I'm stoked. Should be a lot of fun in the z. Final numbers are below...
This is at 40 total. My dyno guy doesnt recommend a street engine running at 40 so we set it back to 35.
Good numbers! That's a hoss right there, good job.
Thanks! From the start, I told him I wasnt there to push the motor to its limits. I wanted to get it running good and see what I was working with/built. If we wanted and my check book would of allowed, (it wouldnt) we could have of played around with it more and found out. It runs like a champ. No noises. Very smooth and sounds great. Even better at 6500rpm!!
Well done Z.
Give us a rundown on the parts used (to save me from going back to your build thread) if you don't mind.
All the good stuff like your calculated SCR/DCR, cam specs (installed position), heads, etc.
Dyno headers...?
GM 010 Block .030 over.
Scat 9000 3.75 Stroke Crank.
ATI Super Damper.
Molnar 5.7 Rods.
Speed pro flat top w 4 eye relief pistons.
Total Seal Rings.
King Rod & Main Bearings.
Durabond Cam Bearings.
Custom Cam From Powell Machine- 232 - 233 @.050 110lsa, around 550 lift. Hyd roller installed straight up.
Comp cam roller lifters and 1.52 rockers.
Avon Pro gear timing set.
Cloyes 2 piece timing cover.
Dart Pro 1 heads w/ 26918 springs, milled from 72cc to 65cc, and a killer valve job.
Canton rr pan 15-244.
RMP air gap.
Holly 750 DP.
Hedman LT headers/ Dyno guy had same ones we used for dyno.
All ARP bolts internal and some external
Brother, if you're running a stock 700r4 behind that hoss it'll be short lived. My 383 only puts out around 25 numbers less than yours on HP/torque and the stock transmission didn't live three months behind it. The new level 3 Raptor 700 transmission is night and day in comparison and it's obvious that I was losing a lot of power through the stock tranny. I went with a 2600 stall converter that PATC built to match the set up I'm running in my IROC.
Brother, if you're running a stock 700r4 behind that hoss it'll be short lived. My 383 only puts out around 25 numbers less than yours on HP/torque and the stock transmission didn't live three months behind it. The new level 3 Raptor 700 transmission is night and day in comparison and it's obvious that I was losing a lot of power through the stock tranny. I went with a 2600 stall converter that PATC built to match the set up I'm running in my IROC.
I know. I guess I wouldnt call it stock, but prob close too. I guess I'm debating on weather I want to have it rebuilt or buy a new one... And if I go new, do I stick with the 700 or go to a 400 or 350. For now I'm going to do some research and save up over the winter. More than likely I'll stick with the 700 because I like the od and gearing.
Interesting thing about the 40 degrees of timing. You would have thought that with those heads, which I understand have an efficient and compact combustion chamber, that best power would be made with less advance.
Another question about the headers: Size? They look to be 1 3/4". How about the collector? Was there an extension of any length? You would think about 18" or so with that being sort of a fall back position (as opposed to having the collector end right at the flange.)
Edit: Looking at the dyno pics I can see a collector extension but can't tell the length. I'm guessing your dyno guy knows what's needed here. Just a bit of info for my dyno files...
You know i never asked. Its kinda like when you go to the doctor.... You have tons of questions before you go but forget when you are there. Plus the clock was ticking... I believe they were 15/8 headers... and the extension was maybe 18 inches long. Pretty much an adapter from the collector to his large exhaust flex pipe that ran out of the building.
Yeah, it hates 30, 31,32,33, deg timing. Well doesnt hate, but doesnt make as much power. I lost close to 50 hp when we went from 40 to 32 deg.
He thought the same things about the heads. Said several times that he thought it woulda liked less timing also.
Of course the obvious question is whether your timing marks are accurate (if I don't mention it someone else will...). Other than that, it's what your engine wants. Some guys pay no attention to the number, just the performance.
Did you model this engine in a simulation program? I had been discussing that with someone but I've kind of lost track.
Last edited by skinny z; 11-07-2016 at 06:43 PM.
Reason: Clarity
I set the marker at tdc when I was checking the cam. So I know its close. However I did have to take it off and there is some slop in the 2 1/4 inch bolts that hold it on I noticed when putting it back on. But not 5* worth... But it is worth checking. Reguardless, its where ever it wants to run best is where its going. But 40 total seems like a lot. When I get it rolling next year, I will likely find a place to do some wheel dyno runs to get even a better tune. Or track time some weekends.... Not sure yet.
As the for the simulation- Yeppers, My buddy Skinny did.
You can double check your timing mark with a screw in piston stop, just screw it into the number one spark plug hole and crank the engine over by hand until it stops. Make a pencil mark on the balancer where the pointer is pointing, then repeat the process in the opposite direction; top dead center will be exactly half way between the two marks.
483 @ 4100 vs 452 @ 4500
452 @ 5600 vs 460 @ 6000
You blew the torque estimate out of the water (nice and flat too). Horsepower was pretty close.
The simulation pushed the rev range a little higher too. I seem to recall something with the way I had to input the cam specs. Doesn't look like you have any issues with valve control. HP only drops off 6 HP after peak @ 5600. That valvetrain should go to 7000. At least mine has.
Valve springs worked great. The highest rpm we pulled was 6500rpm and it sounded awesome. However, its not worth taking it that high numbers wise. I do wish I would of asked my dyno guy if we could have seen numbers starting from 3000 rpm to see what it has.
Msgt, thats tomorrow after work project. I was thinking the same exact thing, except using my degree wheel, which I shouldn't really need i guess.
Did sound good, real good. Nice work man! Must be quite a feeling for the beast to come alive after putting it together with your own hands.
Should be real fun to drive, but maybe a challenge to get the tires to grip on the street!
Thanks Ult! I plan to eventually do a rear end swap sometime. Id rather not cut this car (L69) up so I am keeping an eye out for a decent roller that I will make mods to to accept wider tires. For now I am going to stuff what will fit and see how it does.
11-05-2016, 09:05 PM
