78 L48 Question
Thread Starter
Racer
Joined: May 2013
Posts: 357
Likes: 15
From: Marshville, NC
78 L48 Question
I am trying to get a base line comparison on this L48 engine with 350 auto trans. The engine appears to run good and strong with no apparent issues. The only upgrade I am aware of is the performer 2101 intake, still has the Q Jet carb.
I have not had the opportunity to check the timing or any other adjustments that may be needed, like I said it accelerates and runs great.
My question is with a stock L48, the car in drive at idle and the accelerator nailed to the floor, should the car break traction? She pulls good and I dont expect a hot rod by any means.This is my weekend go get ice cream car and she looks awesome.
Just wondering what the base line is under these circumstances, thats all.
Cant post pics I am at work.
Thanks
I have not had the opportunity to check the timing or any other adjustments that may be needed, like I said it accelerates and runs great.
My question is with a stock L48, the car in drive at idle and the accelerator nailed to the floor, should the car break traction? She pulls good and I dont expect a hot rod by any means.This is my weekend go get ice cream car and she looks awesome.
Just wondering what the base line is under these circumstances, thats all.
Cant post pics I am at work.
Thanks
Racer
Joined: Sep 2014
Posts: 336
Likes: 14
From: Upstate New York
Ill keep track of this post as I just bought a 79 with the L48. I have not driven it yet. Mine is dead stock. It should boil the tires (yours)....My tire lighting days are over, but I would like to drop a raw 350 4-bolt into mine at some point
Thread Starter
Racer
Joined: May 2013
Posts: 357
Likes: 15
From: Marshville, NC
I understand that and am more than pleased with the car as it is. My question is simple. Should a stock L48 properly tuned break traction from a full throttle start?
Melting Slicks
Joined: Jun 2011
Posts: 3,114
Likes: 592
I am trying to get a base line comparison on this L48 engine with 350 auto trans. The engine appears to run good and strong with no apparent issues. The only upgrade I am aware of is the performer 2101 intake, still has the Q Jet carb.
I have not had the opportunity to check the timing or any other adjustments that may be needed, like I said it accelerates and runs great.
My question is with a stock L48, the car in drive at idle and the accelerator nailed to the floor, should the car break traction? She pulls good and I dont expect a hot rod by any means.This is my weekend go get ice cream car and she looks awesome.
Just wondering what the base line is under these circumstances, thats all.
Cant post pics I am at work.
Thanks
I have not had the opportunity to check the timing or any other adjustments that may be needed, like I said it accelerates and runs great.
My question is with a stock L48, the car in drive at idle and the accelerator nailed to the floor, should the car break traction? She pulls good and I dont expect a hot rod by any means.This is my weekend go get ice cream car and she looks awesome.
Just wondering what the base line is under these circumstances, thats all.
Cant post pics I am at work.
Thanks
Original Goodyear radials & newer BF TA's 255/60/15. never did break the tires loose on good roads. The best way to determine if its running within specs is at the track with 1/4 times. @ 2200ft the best my 78 did was 16 sec. Most would be between 15.7+ sec.
Last year I added a ZZ383. I still cannot break the tires loose on good roads. ( not a chance at the track) Even my 2010 GS corvette cannot break the tires loose. (Again running a auto transmission). I also tested the 2015 Z15 corvette at spring mountain.(auto's) they dont break the tires loose.
So the 78 went from 16 sec to 13.8 with the engine change. My 2010 GS runs 12.95.
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Racer
Joined: Jul 2013
Posts: 257
Likes: 36
I've installed a Summitt top end kit and true dual exhaust. Still does not spin the tires (suspect its the cam and 308 combination). Recently installed a B/M hole shot tc with shift kit, but have not tried it yet (Vette is in paint, did the work during the down time). Hope to do some test runs when the Vette gets out of paint, but sadly do not think it will spin the tires until I change the gears/install a trans brake.
Last edited by hpxt; May 13, 2015 at 02:55 AM.
Thread Starter
Racer
Joined: May 2013
Posts: 357
Likes: 15
From: Marshville, NC
I have the same set up; short answer is no. On a dry road with good tires, the 78 and my 75 with 308 gears/TH auto never spun the tires on WOT.
I've installed a Summitt top end kit and true dual exhaust. Still does not spin the tires (suspect its the cam and 308 combination). Recently installed a B/M hole shot tc with shift kit, but have not tried it yet (Vette is in paint, did the work during the down time). Hope to do some test runs when the Vette gets out of paint, but sadly do not think it will spin the tires until I change the gears/install a trans brake.
I've installed a Summitt top end kit and true dual exhaust. Still does not spin the tires (suspect its the cam and 308 combination). Recently installed a B/M hole shot tc with shift kit, but have not tried it yet (Vette is in paint, did the work during the down time). Hope to do some test runs when the Vette gets out of paint, but sadly do not think it will spin the tires until I change the gears/install a trans brake.
Here is a pic.
Burning Brakes
Joined: Apr 2008
Posts: 1,222
Likes: 93
From: shelbyville West Michigan
I have owned my 1978 L48 since 1980. TH350 auto with 3.08 gears.
Original Goodyear radials & newer BF TA's 255/60/15. never did break the tires loose on good roads. The best way to determine if its running within specs is at the track with 1/4 times. @ 2200ft the best my 78 did was 16 sec. Most would be between 15.7+ sec.
Last year I added a ZZ383. I still cannot break the tires loose on good roads. ( not a chance at the track) Even my 2010 GS corvette cannot break the tires loose. (Again running a auto transmission). I also tested the 2015 Z15 corvette at spring mountain.(auto's) they dont break the tires loose.
So the 78 went from 16 sec to 13.8 with the engine change. My 2010 GS runs 12.95.
Original Goodyear radials & newer BF TA's 255/60/15. never did break the tires loose on good roads. The best way to determine if its running within specs is at the track with 1/4 times. @ 2200ft the best my 78 did was 16 sec. Most would be between 15.7+ sec.
Last year I added a ZZ383. I still cannot break the tires loose on good roads. ( not a chance at the track) Even my 2010 GS corvette cannot break the tires loose. (Again running a auto transmission). I also tested the 2015 Z15 corvette at spring mountain.(auto's) they dont break the tires loose.
So the 78 went from 16 sec to 13.8 with the engine change. My 2010 GS runs 12.95.
Melting Slicks
Joined: Jun 2011
Posts: 3,114
Likes: 592
L48's i thought were 180hp, but either way, my '76 won't break em loose. as to the '10 GS, you must have something wrong or maybe don't know how to disable the traction control. if my '95 LT1 completely stock will smoke the SHT out of the tires without power breaking, your '10 & '15 are not working right...
with 325 tires and good dry roads it just doesn't happen in a auto car.(with a different torque converter(non stock) it may be different)
At sea level the 2010 gs runs 12.4 @ 2200 ft I run 12.95. working just fine (2.73 rear gears). The only way the tires loose grip if I launch at an angle. With good temps and good pavment it just doesn't happen. With the 2015 I tested at springmountain, it was nice and warm and there track just grips with the auto's, the manuals on the other hand where completly different. With launch control you could hear the engine retard power due to slipage. Without launch control much easier to let them spin.
As for performance I look at 1/4 runs. I dont like the usual responce using the "seat of the pants sensors" or I can spin the tires as a performance gauge.
Last edited by cagotzmann; May 13, 2015 at 10:05 AM.
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,170
From: Hermosa
If you want tire spinning install a line lock.
My stock 77 would not spin tires on good pavement with good tires.
Timing changes and a carb overhaul along with headers made a huge difference.
After 2400 stall converter added and a shift kit B$M Th350 it would break the tires loose with the stock motor. 3.08 rear diff.
Bone stock you can't power brake it and get the tires to spin.
My stock 77 would not spin tires on good pavement with good tires.
Timing changes and a carb overhaul along with headers made a huge difference.
After 2400 stall converter added and a shift kit B$M Th350 it would break the tires loose with the stock motor. 3.08 rear diff.
Bone stock you can't power brake it and get the tires to spin.
Burning Brakes
Joined: Apr 2008
Posts: 1,222
Likes: 93
From: shelbyville West Michigan
At the track there is just to much grip. Any mode doesn't matter. From sport mode to fully disabled ( holding the TC button down ).
with 325 tires and good dry roads it just doesn't happen in a auto car.(with a different torque converter(non stock) it may be different)
At sea level the 2010 gs runs 12.4 @ 2200 ft I run 12.95. working just fine (2.73 rear gears). The only way the tires loose grip if I launch at an angle. With good temps and good pavment it just doesn't happen. With the 2015 I tested at springmountain, it was nice and warm and there track just grips with the auto's, the manuals on the other hand where completly different. With launch control you could hear the engine retard power due to slipage. Without launch control much easier to let them spin.
As for performance I look at 1/4 runs. I dont like the usual responce using the "seat of the pants sensors" or I can spin the tires as a performance gauge.
with 325 tires and good dry roads it just doesn't happen in a auto car.(with a different torque converter(non stock) it may be different)
At sea level the 2010 gs runs 12.4 @ 2200 ft I run 12.95. working just fine (2.73 rear gears). The only way the tires loose grip if I launch at an angle. With good temps and good pavment it just doesn't happen. With the 2015 I tested at springmountain, it was nice and warm and there track just grips with the auto's, the manuals on the other hand where completly different. With launch control you could hear the engine retard power due to slipage. Without launch control much easier to let them spin.
As for performance I look at 1/4 runs. I dont like the usual responce using the "seat of the pants sensors" or I can spin the tires as a performance gauge.
Thread Starter
Racer
Joined: May 2013
Posts: 357
Likes: 15
From: Marshville, NC