L92 with ported heads and carb prediction
12-21-2010, 09:15 PM
#1
L92 with ported heads and carb - 2 year bump page 2 I would like your best guess at flywheel horsepower. Just would like a quick sanity check to make sure its going to meet my goals.
Engine setup
Stock short l92
Edelbrock single plane carb intake with Holley 850.
Lingenfelter C&C ported L92 cylinder heads cut 30
Comp 238/240 112 LSA .6xx/.6xx (getting the cam free I know its not ideal) I don't know exact lift, lets call it .625/.625
The headers are inch 7/8 with either collector extensions or mufflers shortly after.
The ignition is going to be handled by the msd controller so we can run a carb.
The compression will be around 11:1.
Thanks!
Engine setup
Stock short l92
Edelbrock single plane carb intake with Holley 850.
Lingenfelter C&C ported L92 cylinder heads cut 30
Comp 238/240 112 LSA .6xx/.6xx (getting the cam free I know its not ideal) I don't know exact lift, lets call it .625/.625
The headers are inch 7/8 with either collector extensions or mufflers shortly after.
The ignition is going to be handled by the msd controller so we can run a carb.
The compression will be around 11:1.
Thanks!
Last edited by spanks13; 10-24-2014 at 12:43 PM.
12-27-2010, 02:54 PM
#4
TECH Enthusiast
How are you going to ask for a estimate when you are being secretive about the cam specs.... knowbody will know..... or be able to give you a close estimate.....lol
So as of now, my guess is 5XX hp and 4XX tq......
Bozz
So as of now, my guess is 5XX hp and 4XX tq......
Bozz
12-27-2010, 05:34 PM
#7
The headers are inch 7/8 with either collector extensions or mufflers shortly after.
The ignition is going to be handled by the msd controller so we can run a carb.
The compression will be around 11:1.
550 at the flywheel is a little low for what we need. What is lacking in this build compared to something making 600 at the flywheel? Cam size? It seems like so many people are making 500rwhp with a fast intake, and the single plane carb intake runs even better than that.
The last thing I want is to go through the trouble and money of doing this build and be short 50 horsepower!
Last edited by spanks13; 12-27-2010 at 05:44 PM.
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12-27-2010, 07:20 PM
#8
TECH Enthusiast
Lol I'm not being secretive...I don't know what the cam card says other than that. Lets call it .625/.625
The headers are inch 7/8 with either collector extensions or mufflers shortly after.
The ignition is going to be handled by the msd controller so we can run a carb.
The compression will be around 11:1.
550 at the flywheel is a little low for what we need. What is lacking in this build compared to something making 600 at the flywheel? Cam size? It seems like so many people are making 500rwhp with a fast intake, and the single plane carb intake runs even better than that.
The last thing I want is to go through the trouble and money of doing this build and be short 50 horsepower!
The headers are inch 7/8 with either collector extensions or mufflers shortly after.
The ignition is going to be handled by the msd controller so we can run a carb.
The compression will be around 11:1.
550 at the flywheel is a little low for what we need. What is lacking in this build compared to something making 600 at the flywheel? Cam size? It seems like so many people are making 500rwhp with a fast intake, and the single plane carb intake runs even better than that.
The last thing I want is to go through the trouble and money of doing this build and be short 50 horsepower!
heads are milled .030
the cam is 112 /advance?
comp is prob going to be higher than 11:1
first thing first, check the ptvc.... because if I am a betting man, you will be touching or extremely close with a 238/242 112 .625/.625
the words in the bold are the key.......
Sounds like flycutting maybe in order...... also pending valve job too....
Bozz
12-27-2010, 07:45 PM
#9
The valve job is being done when the heads are ported. I may be having a brain fart, but how does the cam selection affect static compression ratio? The 112 is lobe separation angle, and a wider LSA should increase PTVc over a tighter LSA like a 109 or 110.
I will definitely check ptv when the cam is here. Its a leftover cam that fit in another engine without flycutting. The bonus is that it is free.
I am looking around casually for a junk head to make into a fly cutter head just in case. I do realize it will be on the tight side. I made this thread to see if this cam will achieve the power we need.
If the pistons do wind up getting fly cut then the cam size will probably increase by a good amount. Its a drag race engine that will only need to run in a window of 2000rpm.
As far as compression ratio goes, they are not flat top pistons. The stock l92 pistons have exhaust valve reliefs in them because of the VVT cam phaser. There are two notches in them that add a little volume to the chamber. Unfortunately we ASSumed that the pistons would have intake valve reliefs as well.
Thanks for the help, I appreciate the replies.
I will definitely check ptv when the cam is here. Its a leftover cam that fit in another engine without flycutting. The bonus is that it is free.
I am looking around casually for a junk head to make into a fly cutter head just in case. I do realize it will be on the tight side. I made this thread to see if this cam will achieve the power we need.
If the pistons do wind up getting fly cut then the cam size will probably increase by a good amount. Its a drag race engine that will only need to run in a window of 2000rpm.
As far as compression ratio goes, they are not flat top pistons. The stock l92 pistons have exhaust valve reliefs in them because of the VVT cam phaser. There are two notches in them that add a little volume to the chamber. Unfortunately we ASSumed that the pistons would have intake valve reliefs as well.
Thanks for the help, I appreciate the replies.
12-29-2010, 10:27 PM
#12
Vic Jr single plane.
Don't take this as defensive, just curious.
550 flywheel horsepower seems low for the combination of parts compared to what I have seen from other builds. That is only roughly 460rwhp.
With the ported heads and extremely free flowing exhaust I don't think you would want a large split on the duration. If anything the only non ideal part is that the LSA is too wide and its a little small.
I have seen lots of ls3 cars claim 500rwhp with a mid 230's cam and stock heads. You guys are saying a bigger cam, ported heads, open exhaust, single plane intake 6.2l engine is not going to make 500rwhp? I am always skeptical of dyno claims, but when people have ls3 corvettes running 10.90 with just a cam and bolt ons I tend to believe it.
Don't take this as defensive, just curious.
550 flywheel horsepower seems low for the combination of parts compared to what I have seen from other builds. That is only roughly 460rwhp.
With the ported heads and extremely free flowing exhaust I don't think you would want a large split on the duration. If anything the only non ideal part is that the LSA is too wide and its a little small.
I have seen lots of ls3 cars claim 500rwhp with a mid 230's cam and stock heads. You guys are saying a bigger cam, ported heads, open exhaust, single plane intake 6.2l engine is not going to make 500rwhp? I am always skeptical of dyno claims, but when people have ls3 corvettes running 10.90 with just a cam and bolt ons I tend to believe it.
12-30-2010, 09:25 AM
#13
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I'd say in the 630-650 Flywheel range, your rwhp numbers will depend on transmission, like mine in circles i've heard eats about 30% to the rear (TH350W/Big stall)
01-02-2011, 05:04 PM
#14
any results?
i didn't know that edelbrock made intakes for use with the L92 heads. i thought the only single plane option was from GM. and from what i understand about those particular intakes...they need ported and port matched to do anything impressive.
i didn't know that edelbrock made intakes for use with the L92 heads. i thought the only single plane option was from GM. and from what i understand about those particular intakes...they need ported and port matched to do anything impressive.
01-02-2011, 07:44 PM
#16
What kind of spacer? Carb spacers?
Not going to have results for probably a few months at least. Still need to buy that expensive *** meziere water pump, get an intake, and a dampener.
Edelbrock has a Vic JR single plane with or without injector bosses for the l92 heads.
Stock the l92 heads flowed 307 @ .650 intake and 199 @ .650 exh w/ 4 inch bore on our flowbench. The head was flowed with clay on the intake and an open port on the exhaust. They are off to Lingenfelter now and I'll post up the flow numbers after they've been ported.
The compression is going to be kept around 11:1 so we can run it safely on the crap 91 octane gas here in California.
I think the build will be right around 600hp flywheel, which would be 510rwhp assuming 15% loss. Anything over 600 is gravy.
Not going to have results for probably a few months at least. Still need to buy that expensive *** meziere water pump, get an intake, and a dampener.
Edelbrock has a Vic JR single plane with or without injector bosses for the l92 heads.
Stock the l92 heads flowed 307 @ .650 intake and 199 @ .650 exh w/ 4 inch bore on our flowbench. The head was flowed with clay on the intake and an open port on the exhaust. They are off to Lingenfelter now and I'll post up the flow numbers after they've been ported.
The compression is going to be kept around 11:1 so we can run it safely on the crap 91 octane gas here in California.
I think the build will be right around 600hp flywheel, which would be 510rwhp assuming 15% loss. Anything over 600 is gravy.
07-14-2011, 07:41 PM
#18
3/4 of the races at our local track got canceled for the year 
Some ******* is trying to shut down California Speedway, and is really going after the drag strip hard. Very limited schedule until the lawsuit calms down.
It kind of put a damper on things for a while. Almost had all the parts together, but lost motivation when we lost the track. Probably going to finish out the year with the LT4 in the car since I'm doing well in points.
I forgot to post flow numbers after having the heads ported. Lingenfelter did a nice job.
The intake flows 348.5 cfm at 650 lift and the exhaust flows 220 cfm @ 700.
Never did get that cam. Going to spec one ourselves, and get something more ideal. Haven't decided yet, but we'll probably flycut the pistons and get a real cam in there. Something like 248/260 with .625 or higher lift.
Some ******* is trying to shut down California Speedway, and is really going after the drag strip hard. Very limited schedule until the lawsuit calms down.
It kind of put a damper on things for a while. Almost had all the parts together, but lost motivation when we lost the track. Probably going to finish out the year with the LT4 in the car since I'm doing well in points.
I forgot to post flow numbers after having the heads ported. Lingenfelter did a nice job.
The intake flows 348.5 cfm at 650 lift and the exhaust flows 220 cfm @ 700.
Never did get that cam. Going to spec one ourselves, and get something more ideal. Haven't decided yet, but we'll probably flycut the pistons and get a real cam in there. Something like 248/260 with .625 or higher lift.
02-02-2012, 10:25 PM
#20
Wow back from the grave! God we've had this engine a long time...
It keeps getting bumped in favor of other, more immediate, projects. Also, the budget took a big hit when my dad grenaded the powerglide in his drag car.
That said we almost have all the parts for it. March - June we don't really run much and we're hoping to have the car ready for the summer.
We decided on a cam grind. Its 239/252 on 110 .600/.600 that comp did for us. Haven't had it in the engine yet to check piston to valve clearance. There's a slim chance it may have enough clearance, but more than likely it'll be too close.
The rockers are headed out to CHE to be bushed.
UPS dropped off the Vic Jr. single plane intake a couple days ago.
When the rockers are back and we get the ARP hardware it'll be ready to go together!
It keeps getting bumped in favor of other, more immediate, projects. Also, the budget took a big hit when my dad grenaded the powerglide in his drag car.
That said we almost have all the parts for it. March - June we don't really run much and we're hoping to have the car ready for the summer.
We decided on a cam grind. Its 239/252 on 110 .600/.600 that comp did for us. Haven't had it in the engine yet to check piston to valve clearance. There's a slim chance it may have enough clearance, but more than likely it'll be too close.
The rockers are headed out to CHE to be bushed.
UPS dropped off the Vic Jr. single plane intake a couple days ago.
When the rockers are back and we get the ARP hardware it'll be ready to go together!