When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
As for other updates, I drained the coolant and pulled the radiator out of the way. With the front cover removed, I can't see the dot on the crank sprocket because the oil pump is in the way. However, using this Google photo as a guide:
You can see how the dot in that photo is lined up with the transition from one flat to the other to the left of the keyway on the oil pump drive. Seeing that, I can surmise that my gears are indeed lined up "dot-to-dot". The timing set is a Cloyes hex-adjust and to add insult to injury, it was adjusted with 2 degrees of retard (tilting the curve to pick up a little bit at the top but at the loss of some power at the bottom).
I also pulled the intake manifold off to see if there was any craziness going on there. I've seen it before where the knock sensor wires have been trapped between the block & the intake manifold.
However, not the case here. All the runner gaskets look like they were sealing up just fine. I pulled the injectors and will be sending them out to get flowed.
At this point, part of me just wants to yank the cam, lifters & valvesprings out and just start with something else...
Have looked @ each plug individually to identify a bad cylinder? If it is dropping a cylinder under load I would expect to see something with a plug. Is it possible to do a WOT & then a plug reading with a fresh set?
I would degree that cam, I just picked up a digital degree. Makes TDC & lobe centerline a breeze.
Just because you have a big name do the heads I would not assume anything. I had a big name do a set. When I sent them away for verification, the ports had never been touched, only the chambers were polished to make them look pretty. Maybe they are not even the heads you are suppose to have?
What is a realistic expectation power wise in the car? The Mustang dyno backs up your first dyno session, approx. 15% lower on the Mustang.
The heads are visibly ported on the intake side. I've yet to hear a bad review on Greg or Erik, so I'm going to stand by those guys for now.
I pulled the plugs out again when I degree'd the cam and found something new though. Soot at the base of the fire sleeve and plug for Cyl #5. The plug tip itself is clean but it was driven around since the dyno and even if it's half *** firing maybe that was good enough for part throttle. The soot was from an exhaust leak @ cylinder #5. I recently replaced the metal ones gaskets with a pair of the Percy's carbon.
So, the common theme so far in this thread is probably my best bet at this juncture... new set of plugs, new set of wires and see where it stands. A test & tune night might not be bad either but I'd like to get this re-dyno'd first in case a miracle happens and I end up needing more fuel. I'm also going to order a set of pushrods. Since I'm only getting 1/2 turn @ 22 lbs/ft using the EO/IC method, I'd be looking at a longer set @ 7.700, correct?
Thanks for the suggestions, guys!
Ryan
P.S. Ringram: That was one of the first things we looked at on the Dyno, no restrictions. It's a pretty big filter.
Final Dynojet number was 515whp (SAE). I'll see if I can grab some screenshots.
A header/exhaust C6/Z06 dyno'd right after me and put down 451whp. I'm done.
In the last 3 months:
- leak down test performed, "worst" cylinder was only 6%
- Degreed cam, it was spot on
- removed the pass valve cover baffles (light tapping spotted)
- .025" longer pushrods (Tick 3/8" 7.70")
- new BTR Platinum dual valve springs, replaced the stem seals
- Comp trunnion upgrade (I had it apart anyway)
- sealed the rocker sarm tud threads with RTV... No more smoke on heavy decel
- new TR6 plugs
- new MSD 8.5's wires
- changed exhaust to SS mandrel bent dual 3", merged to single 3.5" Dynomax Ultraflo
Nothing, by itself, made any appreciable difference except maybe the exhaust. There was ~10hp peak found there, I'll have to get the graphs and overlay old vs new.
The car put down 430whp on a Mustang dyno... They then re-calibrated following the procedure given to them by Mustang. My car jumped to 500whp...backed it up on a Dynojet at 515whp.
It "is what it is", as the saying goes. I'm sure I could go to a "happier" dyno and put down close to 550. Hell, I had 540 uncorrected on this Dynojet. When Spring comes though, I'll head to the drag strip. Thanks for the help, guys!
Well 3.5 pipe exhaust is 9.62sq inches and since an inch of pipe flows 112cfm that's about 1000cfm. Generally for zero loss you should have 2.2cfm ber BHP so Id suggest your exhaust was only supporting around 450fwhp with zero loss.
In order words drop your y pipe and run open headers. The Y pipe is still going to be restrictive. I thought you were running dual 3" which would support over 700fwhp.
Do some research and see what your calcs show. Most/All LS7 stuff is dual 3" so Id definitely be looking there IMO.
Well 3.5 pipe exhaust is 9.62sq inches and since an inch of pipe flows 112cfm that's about 1000cfm. Generally for zero loss you should have 2.2cfm ber BHP so Id suggest your exhaust was only supporting around 450fwhp with zero loss.
In order words drop your y pipe and run open headers. The Y pipe is still going to be restrictive. I thought you were running dual 3" which would support over 700fwhp.
Do some research and see what your calcs show. Most/All LS7 stuff is dual 3" so Id definitely be looking there IMO.
Bingo. A 3.5" single has similar flow to 2.5" duals. The Formula in my sig picked up 3mph going for a 2.5" dual setup with restrictive mufflers to an open X pipe. You have a very big engine trying to flow a lot of air exhaling through a straw.
Yep, plus every time OP touches the exhaust he gets glimpses of gains.
Easiest and cheapest test of all is to drop Y pipe on the dyno and see what open headers do. Im betting good gains will be the result.
Hopefully the headers are also semi decent. I guess more exhaust lift & or duration could help crutch things too.
The RX7 swap headers are far from optimum so it will likely never see the same power it would in an F-body or vette but it should be making more than it is.
After all of the crap he has gone through he could have pulled the engine back out and put it on an engine dyno with a set of test headers and see what it makes. That would answer all of the questions I think. If it makes 675fbhp and drops to 620bhp with the swap headers you could attribute another 15-20bhp drop for the Y pipe setup and that would put you at 600bhp which is about with it seems to be making right now.
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.
