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Dewey316 The Lama
Joined: 08 Jan 2004 Posts: 7295 Location: Bringing the tech
1990 Chevrolet Camaro RS
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Posted: Tue Sep 05, 2017 6:23 am Post subject: |
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Do you have a plot that includes AFR with the torque curve, and is it being pulled from a separate WB? It shows you are at some point going to 10.1 as the min AFR, I would be interested to see where that is in relation to the torque curve. |
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QwkTrip 11sec Club
Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Tue Sep 05, 2017 7:11 am Post subject: |
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No, I don't have the plot of the tailpipe wide-band, but my wide-band works just fine (better actually because more preferred position in exhaust). The number drops to 10's at the end of run when letting off throttle. |
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QwkTrip 11sec Club
Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Thu Sep 07, 2017 9:59 am Post subject: |
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Did a few more dyno runs removing pieces of the exhaust. Exhaust is not holding it back. Starting to look like cam install again or something funky about the engine combo. |
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Dewey316 The Lama
Joined: 08 Jan 2004 Posts: 7295 Location: Bringing the tech
1990 Chevrolet Camaro RS
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Posted: Thu Sep 07, 2017 10:44 am Post subject: |
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you don't have the normal break-up from valve float, but maybe it is a very smoothed out graph? Can you hear any change in the engine when your power starts to drop off? |
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QwkTrip 11sec Club
Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Thu Sep 07, 2017 12:57 pm Post subject: |
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No, you can't even feel it while driving because I have to pedal the car on the street anyway. It is only something you would feel at the drag strip where you can run the car all out.
You can feel it slow some on the dyno when the power lays over but it will pull out to redline (130 mph in 4th gear). The torque curve is on a straight line downward, not the typical rounded over shape. That makes the power curve just kind of flatline out to 7000 RPM rather than the typical cliff dive. |
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Twilightoptics Hardcore (12sec Club)
Joined: 13 Jan 2004 Posts: 9191 Location: Auburn , WA
1987 Chevrolet Camaro IROC-Z
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Posted: Thu Sep 07, 2017 9:18 pm Post subject: |
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I wasn't thinking exhaust restriction. What about air filter, plumbing from air filter, throttle body, etc. In fact, a large exhaust shouldn't let the engine create a vacuum. If it can't get it out, it can't suck to get it in.
Also, a 3kpa variance at WOT is completely acceptable for a map sensor and depending on baro/temp at the time: 100kpa is commonly "zero vacuum."
You can read all you want about what AFR works for some other person's setup. 12.8 is great and safe for most engines. Only way to compare is on a dyno and change YOUR setup. Even if it's the same parts, your engine is still different.
When I've tuned on a dyno I make a few runs changing timing and find that as best (with a safe AFR.) Then go after AFR. Once I have peaks with AFR, changing total timing 3-4 degrees up or down hasn't made any further improvements. _________________ A redline a day keeps the carbon away! |
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QwkTrip 11sec Club
Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Tue Sep 12, 2017 7:48 am Post subject: |
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I just bought an LS7. |
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Dewey316 The Lama
Joined: 08 Jan 2004 Posts: 7295 Location: Bringing the tech
1990 Chevrolet Camaro RS
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Posted: Tue Sep 12, 2017 8:19 am Post subject: |
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QwkTrip wrote: | I just bought an LS7. |
That is one way to solve things. Ditch your 427, and buy a turnkey 427, lol. |
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QwkTrip 11sec Club
Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Tue Sep 12, 2017 2:41 pm Post subject: |
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Yep.
It actually makes quite a lot of difference jumping to the big bore, shorter stroke with LS7 heads. This should walk all over my medium bore stroker and have better drivability too.
This is a 10K mile stocker being pulled from some guy's car at a famous speed shop in PA. Apparently the guy wanted a wild LSx engine so they pulled the stock one out to start from scratch.
I'll swap cam, add an MSD intake, and deck the head a bit. That's pretty much it other than some reliability improvements to the valvetrain. And whatever alterations are needed for compatibility with my car. Making a lot of power with an LS7 is sooooooo easy! |
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Dewey316 The Lama
Joined: 08 Jan 2004 Posts: 7295 Location: Bringing the tech
1990 Chevrolet Camaro RS
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Posted: Tue Sep 12, 2017 4:59 pm Post subject: |
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I knew that you not being in project mode was to good to last very long. |
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QwkTrip 11sec Club
Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Tue Sep 12, 2017 5:18 pm Post subject: |
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Ya, this is going to be fun prepping the engine. Especially since the car is still a driver. No burden to feel like I got to get it running again. |
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izcain 9sec Club
Joined: 09 Sep 2006 Posts: 1306 Location: Port Angeles WA
1983 Chevrolet Camaro Z/28
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Posted: Fri Oct 06, 2017 7:49 am Post subject: |
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This is awesome to hear!
Those LS7's sound so good when up in the 7k range lol
Are you going to go thru the change to dry sump with it or are you putting a normal pan on? _________________
1983 Z28 383 + 201ci more = New Heart for this season!
9.17 @ 148 |
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QwkTrip 11sec Club
Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Sat Oct 07, 2017 4:50 pm Post subject: |
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I'm doing a wet sump conversion. I have nowhere to put a dry sump tank... they are HUGE! Quite a few parts transfer over from my old engine (oil pan, FEAD). Just need to buy an oil pump, and I'm going to upgrade to an ATI damper.
Picked up a barely used set of Mamo 265 Trick Flow heads this weekend; Mamo Terra Yella rockers; and Johnson short travel, link bar lifters. Still hunting for a used Mamo MSD intake. And still investigating what cam to use. Been talking to Mamo about buying all this stuff from him but the deals are falling in my lap and I can't turn it down. Not sure if he'll spec out a cam for me if I keep buying used stuff.
Stock LS7 manifolds are dirt cheap, but the fuel rails get $200 for some odd reason. I have Nasty Performance fuel rails today, and for $250 I can have Nasty Performance make me another set of fuel rails that are compatible with the tall injectors from my current engine. That's a no brainer.
Trying to figure out if I need to upgrade fuel pump. I have a Racetronix pump in LS1 F-body fuel tank. This engine is going to be a solid 700 Hp. |
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izcain 9sec Club
Joined: 09 Sep 2006 Posts: 1306 Location: Port Angeles WA
1983 Chevrolet Camaro Z/28
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Posted: Mon Oct 09, 2017 9:57 am Post subject: |
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This is beginning to sound like one hell of a beast lol. This should provide some seat of the pants thrills for sure lol _________________
1983 Z28 383 + 201ci more = New Heart for this season!
9.17 @ 148 |
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QwkTrip 11sec Club
Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Sat Oct 14, 2017 9:39 pm Post subject: |
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Sweet - I just scored a barely used Mamo MSD intake too. That wraps up the hunt for used parts and now I can buy my new parts and get to wrenching. |
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izcain 9sec Club
Joined: 09 Sep 2006 Posts: 1306 Location: Port Angeles WA
1983 Chevrolet Camaro Z/28
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Posted: Mon Oct 16, 2017 11:34 am Post subject: |
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Going to be saving the other motor for a backup then? _________________
1983 Z28 383 + 201ci more = New Heart for this season!
9.17 @ 148 |
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QwkTrip 11sec Club
Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Mon Oct 16, 2017 7:57 pm Post subject: |
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Depends on when the swap occurs. My bank account is feeling the strain right now so I would probably sell the engine if it is pulled this winter. Come next spring I may not care so much and end up keeping it. Honestly though, I don't know what I would do with it and the smart thing to do is sell.
The engine has less than 3K miles on it. |
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QwkTrip 11sec Club
Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Sat Oct 21, 2017 9:51 pm Post subject: |
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I don't have an intake manifold after all. I bailed on it because there was getting to be too much horse trading involved between two friends on the other side. Still on the lookout for a used one.
Getting closer to choosing a cam. Been crunching a lot of numbers over the last few days and reverse engineering some really successful builds. It is helping me get a better understanding what I should do. |
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QwkTrip 11sec Club
Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Fri Dec 22, 2017 3:15 pm Post subject: |
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I wish I could display pictures here. Getting pretty dry just typing messages.
I have a cam now for the LS7. I had Tony Mamo spec it out. Funny thing about it is that the cam is almost identical to what I have today. Literally almost a clone other than 1 degree less overlap.
Comp Cams LSG lobes
240/254 114+3
The intake manifold will arrive in a few days. It is an MSD Airforce intake that has been ported by Mamo. The intake alone is worth 40 RWHP.... no joke! Turns out the LS7 intake manifold is not as good as the LS3, so swapping to a good intake yields big gains with the LS7.
Targeting 11.6 - 11.7 static compression ratio with this build, and 0.035" quench. Next step is to open up my engine for the first time and measure things out to finalize gasket thickness and how much to mill the heads. |
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QwkTrip 11sec Club
Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Mon Jan 22, 2018 10:49 pm Post subject: |
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Oh, good, the site is back up again. Just in time to ask for advice.
What is the proper way to measure piston height out of deck for purposes of determining quench? From what I am gathering, the measurement should be taken with piston level (not rocked), or directly above the pin.
Using a piston bridge, I put a dial indicator at 12 and 6 o'clock positions on the piston, rocked the piston by hand until level (both readings roughly the same) and then took readings. If numbers were slightly different then I averaged the values. After that I would double check that piston really was a TDC.
I also took another set of measurements with dial indicator at center point of piston. Pretty much gave the same numbers except for one piston where it seems center is 0.001 lower than the outer portion of the piston.
Looks like the deck height is different on each side of the engine, or the crank has aligned a bit offset of center. Is this anything to be concerned about?
cyl 1.... .0030
cyl 3.... .0035
cyl 5.... .0030
cyl 7.... .0030
cyl 2.... .0055
cyl 4.... .0065
cyl 6.... .0060
cyl 8.... .0060 |
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