Finished L98 cam swap.
#1
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Car: 2007 Corvette Z06
Engine: LS7
Transmission: 6 speed
New 1/4 mile times w/L98 cam.
Finally finished after 3 days and ~15hrs of work, also put in some 1.6RR i had lying around, LT4 retainers, 848 crane springs (~98lbs seat pressure at 1.72 install height). I left the intake and TBI stock. What's funny is that the L98 cam is actually quieter at idle and I'd say idles smoother than the stock peanut cam. Here's the specs @ .05 from the tech data page:
L98 ...049 p/n
207 int, 213 ext lobe sep. 117 .442" lift int .457" lift exh (w/1.6)
Peanut ...155 p/n
179 194 .350" .384" 109 lobe sep.
So I assume it's the lobe sep. that helped the idle. It feels about the same low end, but pulls much better up top, shifted at 5500+ rpms(still pulling).
I'll get track times on wed. I'm thinking real low 14's.
Any thoughts on to which is now the "limiter", the stock TBI heads or the stock intake manifold? I don't think it's the stock TBI or air cleaner housing.
L98 ...049 p/n
207 int, 213 ext lobe sep. 117 .442" lift int .457" lift exh (w/1.6)
Peanut ...155 p/n
179 194 .350" .384" 109 lobe sep.
So I assume it's the lobe sep. that helped the idle. It feels about the same low end, but pulls much better up top, shifted at 5500+ rpms(still pulling).
I'll get track times on wed. I'm thinking real low 14's.
Any thoughts on to which is now the "limiter", the stock TBI heads or the stock intake manifold? I don't think it's the stock TBI or air cleaner housing.
Last edited by Beast5spdGTA; 03-12-2003 at 11:58 PM.
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Car: 2007 Corvette Z06
Engine: LS7
Transmission: 6 speed
You would think air cleaner, but I ran a brand new paper 14 x 3" drop base open element, vs. my k&N air filter(82-84 cowl(does nothing IMO)) and modified stock housing(removed heat stove valve), I actually went ~.1 sec and .5 mph slower with the open element. I did definately notice a difference when removing the heat stove valve, try it putting the stocker on some warm day.
#4
Exhaust manifolds are your biggest restriction. If you do full exhaust (headers, cat, cat back) you could see up to a 30hp increase at the wheels. But dont be upset if you dont see a full 30hp. It should be in the 20 - 30 range.
#5
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Car: 2007 Corvette Z06
Engine: LS7
Transmission: 6 speed
See my sig in the first post, I have full exhaust: mildly ported edelbrock 1 5/8" headers, 3" randomtech cat, hooker cat-back. It would've been pretty sweet(I'd say impossible) to run 14.7 @ 93 with the stock exhaust though.
I think I'm gonna give the open element another try.
I think I'm gonna give the open element another try.
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sounds liek ti worked otu pretty good then. what kind of tme do you have into programming the chip? any dead spots in teh power band or is it smooth all teh way up?
good work man
later
tim
good work man
later
tim
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Car: 2007 Corvette Z06
Engine: LS7
Transmission: 6 speed
It's actually on the stock program(from diy-efi) now with the base timing set at 8* and 93 octane if you can believe that, I was on the hypertech streetmaster(which isn't much different than the stock one). I do have everything to burn chips now, but I've only burned 2 chips so I'll start playing around a little with it (I'm set up with moates adapter/switcher).
No dead spots, I think it's running a little rich though, especially around idle,... only noticable driveability problems is idle with AC, will almost stall when the comp. kicks in, but I'm gonna try just stepping the target idle up a little and see if that helps.
If feels like it's loosing a little of the top end punch now, but that may just be me getting used to it. Tried the open element, with no difference. I haven't even hooked a scan tool to it yet though. If it doesn't rain wed, I'll get a new time slip.
No dead spots, I think it's running a little rich though, especially around idle,... only noticable driveability problems is idle with AC, will almost stall when the comp. kicks in, but I'm gonna try just stepping the target idle up a little and see if that helps.
If feels like it's loosing a little of the top end punch now, but that may just be me getting used to it. Tried the open element, with no difference. I haven't even hooked a scan tool to it yet though. If it doesn't rain wed, I'll get a new time slip.
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Car: '91 t-top RS; '91 hrdtp Z28
Engine: LO3;383tpi
Transmission: 700r4;very nice 700r4
Axle/Gears: 4.10 zt posi, 3.70 auburn
Beast, you have a real strong running engine and some nice times. Assuming the L98 cam gets you low 14's, an intake swap could get you into the 13s, which would be a major feat on the stock heads. But anyways, when I ditched the stock intake and installed the holley 300-66, the difference was amazing! Definite SOTP and pulled much better up high. In our "mock" quarter mile, I picked up 5 mph with the addition of the intake and 1.6 roller tip rockers. That was before chip tuning as well, which always makes for a nice difference. Swap the intake, it is worth it. Can't wait to see your timeslips. Best of luck
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Car: 2007 Corvette Z06
Engine: LS7
Transmission: 6 speed
Damn the butt meter. Got to teach it to read torque and HP.
Well, track times were rather disappointing. The weather was a little worse (hot and humid) than the last time at the track (my only good excuse).
Got 3 runs in:
1st with open element (paper) shifted ~5200-5300
2.20 60'
9.51 @ 75.11 1/8
14.73 @ 94.78
Went back to stock air filter housing (K&N) shifted ~5500
2.18 60'
9.48 @ 75.32
14.69 @ 94.90 mph
Same (either short shifted 2nd or got knock in 3rd(long time in 3rd))
2.16 60'
9.48 @ 73.67
14.67 @ 94.66 mph
All 3 runs I bogged off the line, I tried holding rpms at 1500-2000 then leaving still bogged. I used to just launch from idle with minimal (~5-10ft) wheelspin then hook. On the highway it pulls like crazy vs stock 80-110+ mph. So that's probably why I was hoping for better times, couldn't feel the lost of low end on the street. I think it had a 14.50 @ 95.xx mph in it if I could've got a few more runs since my launches were pretty crappy.
On a side note I did beat my friend's LT1(missed shift) and a new 350Z on the last run he ran 14.73 @ 98.03 mph(can't drive 2.49 60')
I'm pretty sure I'll get the preformer carb intake on this weekend and start trying to tune her up a little. I'm pretty sure it has enough fuel (too much down low maybe), but the spark needs some attention.
Got 3 runs in:
1st with open element (paper) shifted ~5200-5300
2.20 60'
9.51 @ 75.11 1/8
14.73 @ 94.78
Went back to stock air filter housing (K&N) shifted ~5500
2.18 60'
9.48 @ 75.32
14.69 @ 94.90 mph
Same (either short shifted 2nd or got knock in 3rd(long time in 3rd))
2.16 60'
9.48 @ 73.67
14.67 @ 94.66 mph
All 3 runs I bogged off the line, I tried holding rpms at 1500-2000 then leaving still bogged. I used to just launch from idle with minimal (~5-10ft) wheelspin then hook. On the highway it pulls like crazy vs stock 80-110+ mph. So that's probably why I was hoping for better times, couldn't feel the lost of low end on the street. I think it had a 14.50 @ 95.xx mph in it if I could've got a few more runs since my launches were pretty crappy.
On a side note I did beat my friend's LT1(missed shift) and a new 350Z on the last run he ran 14.73 @ 98.03 mph(can't drive 2.49 60')
I'm pretty sure I'll get the preformer carb intake on this weekend and start trying to tune her up a little. I'm pretty sure it has enough fuel (too much down low maybe), but the spark needs some attention.
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Car: 2007 Corvette Z06
Engine: LS7
Transmission: 6 speed
One of these days, I'll go down to the steel store and get some steel to make LCA brackets since mine point down, box the LCA, and make some SFC. I already have poly tranny and torque arm bushings.
But traction isn't my problem right now I've cut 2.10 60' before with a nice launch IMO and cut a 2.16 60' tonight bogging everytime.
(bogging IMO = almost like stalling, meaning I had so much traction that my rpms dropped from 1500-2000 to ~ 1000 or less rpm off the line)
This is a little off topic, but I usually pull ~4.8 volts at WOT on the MAP sensor. Is that the normal range or should I be able to pull 5.0 volts = no vacuum?
But traction isn't my problem right now I've cut 2.10 60' before with a nice launch IMO and cut a 2.16 60' tonight bogging everytime.
(bogging IMO = almost like stalling, meaning I had so much traction that my rpms dropped from 1500-2000 to ~ 1000 or less rpm off the line)
This is a little off topic, but I usually pull ~4.8 volts at WOT on the MAP sensor. Is that the normal range or should I be able to pull 5.0 volts = no vacuum?
#12
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Car: check
Engine: check
Transmission: check
Originally posted by Beast5spdGTA
This is a little off topic, but I usually pull ~4.8 volts at WOT on the MAP sensor. Is that the normal range or should I be able to pull 5.0 volts = no vacuum?
This is a little off topic, but I usually pull ~4.8 volts at WOT on the MAP sensor. Is that the normal range or should I be able to pull 5.0 volts = no vacuum?
If you figure baro was 102 or 103 KPa then the drop would be 1.2 to 2.2 KPa for about 0.6" of vacuum. (0.29" per KPa).
RBob.
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With the way your car has improved, I wonder if my car really did start out life as an LO3 or something else...
It kinda makes me wonder about the cam inside my car if it really is the peanut cam... with 1.6 rockers and with the log headers and y-pipe I was able to break into 91 mph, pulled a miracle 92 mph a few times with shallow staging and good shifts.
This is with open 3.23, no traction mods, and an auto.
Think if I go headers and y-pipe (which given the current tbi lo3 headers should give a gain of a few mph at the least)...
It kinda makes me wonder about the cam inside my car if it really is the peanut cam... with 1.6 rockers and with the log headers and y-pipe I was able to break into 91 mph, pulled a miracle 92 mph a few times with shallow staging and good shifts.
This is with open 3.23, no traction mods, and an auto.
Think if I go headers and y-pipe (which given the current tbi lo3 headers should give a gain of a few mph at the least)...
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Car: 2007 Corvette Z06
Engine: LS7
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RBob, I guess I'll have to go find a conversion table, I was under the impression each volt = 20 kpa.
#15
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Originally posted by Beast5spdGTA
(bogging IMO = almost like stalling, meaning I had so much traction that my rpms dropped from 1500-2000 to ~ 1000 or less rpm off the line)
(bogging IMO = almost like stalling, meaning I had so much traction that my rpms dropped from 1500-2000 to ~ 1000 or less rpm off the line)
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Car: 2007 Corvette Z06
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I did a little higher each run, that's why I said I think it had a little more in it that night if I could've got a good launch.
BTW tuning sucks, but I'm sure (hoping) it will be worth it in the end.
BTW tuning sucks, but I'm sure (hoping) it will be worth it in the end.
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Transmission: check
Originally posted by Beast5spdGTA
RBob, I guess I'll have to go find a conversion table, I was under the impression each volt = 20 kpa.
RBob, I guess I'll have to go find a conversion table, I was under the impression each volt = 20 kpa.
KPa = (V * 18.801) + 10.415
The V is the MAP voltage as read from the sensor. Can plug this into Excel and make up a chart if you'd like.
RBob.
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Car: 1999 Yamaha Banshee
Engine: 379cc twin cyl 2-stroke stroker
Transmission: 6 spd manual
Axle/Gears: 14/41 tooth
Originally posted by Beast5spdGTA
I did a little higher each run, that's why I said I think it had a little more in it that night if I could've got a good launch.
BTW tuning sucks, but I'm sure (hoping) it will be worth it in the end.
I did a little higher each run, that's why I said I think it had a little more in it that night if I could've got a good launch.
BTW tuning sucks, but I'm sure (hoping) it will be worth it in the end.
#20
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Car: Turbo Buick
Engine: 3.8 V6
You probably need a slightly more aggressive timing curve
Ive noticed in my experience that when you start messing with the LO3, like cam and manifold etc itll tend to lose low end and I find that its because the stock programming is really wimpy on the low end high load timing. Like the 100 kpa line have it ramp up a little faster.
Ill bet youll get the low end back with that. Might need a little more pump shot too but im not sure thats the case what with you only changing the cam this time.
Other than that, thats an excellent trap speed, nearly 95 mph! thats awesome. Im pretty sure with a little bit of tuning youll get the ET's to match. A new manifold will certainly improve upon that even more.
By the way, thanks for your posts, they are refreshing. They are well written and they include track times. Imagine that.
Ive noticed in my experience that when you start messing with the LO3, like cam and manifold etc itll tend to lose low end and I find that its because the stock programming is really wimpy on the low end high load timing. Like the 100 kpa line have it ramp up a little faster.
Ill bet youll get the low end back with that. Might need a little more pump shot too but im not sure thats the case what with you only changing the cam this time.
Other than that, thats an excellent trap speed, nearly 95 mph! thats awesome. Im pretty sure with a little bit of tuning youll get the ET's to match. A new manifold will certainly improve upon that even more.
By the way, thanks for your posts, they are refreshing. They are well written and they include track times. Imagine that.
#22
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A 95 is about 14.2-3 on a good hook in a 3rd gen, I'd say you need about a 1.9 60'. Man your blasting your way to 13s on stock heads, great job!
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Car: 91 Z28 Vert
Engine: 305
Transmission: TKO
Axle/Gears: 3.55 10-bolt
Oh.....nice post....I cant wait to throw my L98 Cam in next week.....I have been putting mine off for a while....I think its time now! Good stuff man!
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Car: 91 Z28 Vert
Engine: 305
Transmission: TKO
Axle/Gears: 3.55 10-bolt
Geez I guess I am the one to blame for that one eh!
Just looking for some insight into my swap I have planned.
Just looking for some insight into my swap I have planned.
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