Need Help with Decision: Should I get another cam? 408/L92/GMPP SinglePlane
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Need Help with Decision: Should I get another cam? 408/L92/GMPP SinglePlane
Well...... I had to get my heads repaired due to an error in judgement. My car has been down since Nov. I wasnt in a hurry to get it running. Now I am getting anxious to drive it again. Here are the details of the setup:
HKE 408 w/ Diamond Pistons
244/248 Comp XER cam on a 113+2 with a 111 ICL.
Greg Good ported L92 heads with Patriot Extreme Springs
I have only 2 things missing from my setup other than tuning:
Optimized cam for my L92's and intake
New Torque Converter.
My car dyno'd 455rwhp uncorrected with the current cam/converter combination.
So far the wise folks have said to go smaller on the cam and move things to a more usable RPM. And I assume more aggressive on the .200 numbers.
Comp's techline said to just move mine to a 109 ICL and be done with it. How much is there to gain by going with another cam? I dont have a dyno graph and my track times suck so far. Car ran 1.76 60ft and 7.6 @ 96mph on motor and 1.55 60ft and 6.4 @ 108mph on a healthy shot of nitrous. The converter is supposed to stall 3600-3800 on motor and with my weight it is only stalling around 3300-3500 max. I want a 4000-4200 Nitrous stall that hits 5200 on the jug.
What would you do? Should I just concentrate on the tune and converter or go ahead and swap cams while the heads are off?
HKE 408 w/ Diamond Pistons
244/248 Comp XER cam on a 113+2 with a 111 ICL.
Greg Good ported L92 heads with Patriot Extreme Springs
I have only 2 things missing from my setup other than tuning:
Optimized cam for my L92's and intake
New Torque Converter.
My car dyno'd 455rwhp uncorrected with the current cam/converter combination.
So far the wise folks have said to go smaller on the cam and move things to a more usable RPM. And I assume more aggressive on the .200 numbers.
Comp's techline said to just move mine to a 109 ICL and be done with it. How much is there to gain by going with another cam? I dont have a dyno graph and my track times suck so far. Car ran 1.76 60ft and 7.6 @ 96mph on motor and 1.55 60ft and 6.4 @ 108mph on a healthy shot of nitrous. The converter is supposed to stall 3600-3800 on motor and with my weight it is only stalling around 3300-3500 max. I want a 4000-4200 Nitrous stall that hits 5200 on the jug.
What would you do? Should I just concentrate on the tune and converter or go ahead and swap cams while the heads are off?
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As far as idle..... due to the Single Plane intake, my 244/248 is actually too smooth with very little lope compared to most big cammed 346 cars. It is very docile.
pardon the static... it is quieter with a filter/tube on it.
One more thing.... I want too much from my car...... if that makes sense.
5.99-6.15 Track runs hitting it with the jug: 300 shot.
6.80-7.20 -Track runs on motor (most often due to nitrous accessibility)
Street driving for burgers and beer
30mile drives to the in-laws on the weekend.
Full weight with a/c
and an occasional run from a roll against some buds.
Am I asking for too much?
pardon the static... it is quieter with a filter/tube on it.
One more thing.... I want too much from my car...... if that makes sense.
5.99-6.15 Track runs hitting it with the jug: 300 shot.
6.80-7.20 -Track runs on motor (most often due to nitrous accessibility)
Street driving for burgers and beer
30mile drives to the in-laws on the weekend.
Full weight with a/c
and an occasional run from a roll against some buds.
Am I asking for too much?
#4
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It looks like you are going in the right direction on your setup. Putting down those numbers with a stall converter unlocked isn’t bad and a good starting point. Like most combinations of this type you have to dial in the car to the motor. You are making a great deal of power at the crank with your engine so you just have to rub on the other things that can make this come together for you. Not many people can hit the nail on the head first time around, (just look at Tony Mamo's posts on his setup). From what I’ve seen here the intake you are running gives up some torque on the bottom end and will make your car feel sluggish in that range if geared incorrectly. You track time bears this fact out. Without a dyno sheet it’s hard to tell where your converter should stall at or where your rear end gear ratio should be. Your sig says you are like a lot of us and would like to drive your car on the street along with some fun at the track. You can have both if you know where to start. I would evaluate your power band and stall your converter and gear ratio using those numbers. As you said your car is heavy and you will need to setup your stall/ratio’s to address that issue.
On the cam issue you will need to look at the flow numbers that Greg came up with to spec it out. If he ramped up the exhaust flow, this current cam could be a nice place to start and you could move the intake center line around to optimize things. I would assume the head work was accomplished with the intake manifold involved. A good flowing set of heads will mean nothing without a good flowing intake and exhaust. Just take one step at a time and things should work out.
Good Luck,
D.J.
On the cam issue you will need to look at the flow numbers that Greg came up with to spec it out. If he ramped up the exhaust flow, this current cam could be a nice place to start and you could move the intake center line around to optimize things. I would assume the head work was accomplished with the intake manifold involved. A good flowing set of heads will mean nothing without a good flowing intake and exhaust. Just take one step at a time and things should work out.
Good Luck,
D.J.
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no dyno.... rest of the specs are just 4.00 eagle crank, eagle H beams, stock timing chain, gm revised lifters,90mm tb on the elbow. Revs are safe to 7200.... no need to go higher. I dyno'd it but they printed MPH.... so it was useless. If you looked at the graph.... hp and tq where flat as Salt Lake city with a minor drop at 6400ish.
Exhaust is a set of Hooker 1 7/8 longtubes with no cats thru a 3 inch x-pipe and 24 inch twister flow pro true duals dump before the axle made by Hutto.
Here is a non recent pic of the back (anti roll and relocation brackets arent installed):
Last edited by WizeAss; 01-21-2008 at 06:25 AM.
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He didnt touch the intake. I sent him a L76 and then right after he was about finished changed direction and went with the carb style. I felt it would be safer with the Gemini NX plate on the bottle vs spraying to the back 7 and 8 cylinder. I am getting the intake ported now. Nothing major, just moving the 2 middle posts from the inside runners down and back, gasket matching the ports at the bottom, and blending the runners to the ports. honestly.... I really was having second thoughts about porting it..... the car has no intake velocity as it is NA.....larger runners would only kill off more.
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I'm really not tuned into eight mile times but it would be interesting to know at what rpm you cross the finish line at in the quarter. If your engine doesn't lay down on the top end and will pull to 7200, (still making power at that rpm) then you will need to be pulling a gear to take advantage of that power band. The proper converter to hit the tires and gearing to pull all the way through in your engines power band.
D.J.
D.J.
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I'm really not tuned into eight mile times but it would be interesting to know at what rpm you cross the finish line at in the quarter. If your engine doesn't lay down on the top end and will pull to 7200, (still making power at that rpm) then you will need to be pulling a gear to take advantage of that power band. The proper converter to hit the tires and gearing to pull all the way through in your engines power band.
D.J.
D.J.
I have 3.89 gears.....
I pull 3rd with the bottle and 2nd without just barely.
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I would get a new cam designed personally. Here are some cam spec's that I have for a 403 engine, but haven't had time to test just yet:
296/302 adv. dur.
236/247 @.050" dur.
.603"/.621" lift w/1.7's
111* LSA + 5* (106 ICL)
296/302 adv. dur.
236/247 @.050" dur.
.603"/.621" lift w/1.7's
111* LSA + 5* (106 ICL)
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Hey Wiseazz (that just makes me laugh), if the dyno shop saved your run file, all they have to do is open it, right click MPH, choose engine speed, and it will change the graph to RPM. They could then export the graph, and email it to you.
The reason I'm telling you this, is because I'd like to see it too.
Just because you can spin your engine to 7200 doesnt mean its making power up there. The graph could tell alot.
The reason I'm telling you this, is because I'd like to see it too.
Just because you can spin your engine to 7200 doesnt mean its making power up there. The graph could tell alot.
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Hey Wiseazz (that just makes me laugh), if the dyno shop saved your run file, all they have to do is open it, right click MPH, choose engine speed, and it will change the graph to RPM. They could then export the graph, and email it to you.
The reason I'm telling you this, is because I'd like to see it too.
Just because you can spin your engine to 7200 doesnt mean its making power up there. The graph could tell alot.
The reason I'm telling you this, is because I'd like to see it too.
Just because you can spin your engine to 7200 doesnt mean its making power up there. The graph could tell alot.
http://verizonguyyp.googlepages.com/...ips&dynographs
the others where either lower or had multiple 1200rwtq spikes.... I assume due to the converter.
edit: is this accurate to determine RPM on the last graph?
6600 57 95 141
RPM 1st 2nd 3rd
5500 47 80 118
5600 48 81 120
5700 49 82 122
5800 50 84 124
5900 51 85 126
6000 52 87 128
6100 53 88 131
6200 54 90 133
6300 54 91 135
6400 55 93 137
6500 56 94 139
6600 57 95 141
Last edited by WizeAss; 01-21-2008 at 05:59 PM.
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bit the bullett and ordered a custom grind from Rick at Synergy..... he seems to know what is going on with this L92 head..... although he focuses on mid range torque and I was looking for the number at 5500-7000rpm..... I am sure that it will be satisfactory and a wise choice. What I meant by bullet is potentially going to a smaller cam vs the 244/248....... crazy I tell ya. I have had bigger is better blasted all over tech and the world for a long time... like kicking an old addiction ya know.