Ok my CamaroZ28.com family I made my first runs in my 94 Formula this past Friday. Here is my best time slip:

R/T: .093
60': 1.888
330: 5.498
1/8: 8.514
mph: 81.25
1000: 11.141
1/4: 13.370
mph: 101.24

As I am sure you noticed my 60' was good, and my 1/8th mile was pretty good, however power seemed to drop off quite a bit after the 1/8th. My trap was much lower then I expected. The previous owner ran a best of 13.6@102mph with a 2.2 60'. I am thinking my runs should be trapping about 105-106mph.

Now I am thinking the loss of top end power is in the valvetrain. Perhaps out of adjustment rockers, worn out springs, or lifters. The plugs are new NGK TR55s, and I am running Taylor 8mm wires. The #1 plug wire does have a slight burn from the headers on it, but nothing really bad enough for me to warrant concern.

I do have a slight tick that could be a ticking lifter, or just an exhaust leak. Its coming from the bottom near the header collector which does have some carbon build up by the coupling to the Y pipe. After running I get some backfiring (maybe 2 or 3 immediately following my run after I let off the gas) with my cutout open.

So my LT1 gurus what do you guys (and gals) suggest? Any clue as to where my power has gone to up top?

 

If you have a ticking, it may be in need of a valve adjustment, which could also explain a top end loss.

 

I see nothing in your signature that would warrant your expected MPH. Yes, you are getting good traction and your times look times and mph look good to me, but just because you have good low end power and good 0-60 does not guarantee higher MPH. HP determines your MPH and I don't see where you have the HP to achieve your expected numbers. JMHO

 

Thats exactly what I was thinking. However I was talking with a good friend about adjusting my rockers, and he gave me the impression that LT1s with stock rockers don't get out of adjustment very often at all. That is is very rare. I always thought it was common to need to adjust your valves. I was also thinking old worn out springs could be a cause of it.


Thank you for your input. I really appreciate it. The previous owner has run 102mph traps@13.6 so I expected to atleast see 102mph.

When he had the car it had old plugs, stock stall, warped front rotors, leaking wheel bearings, and grinding rear rotors, 4 18" rims with 275/35s that weighed 60lbs ea., not to mention the differential mains were so loose that one stud was almost completely backed out, and the nut on the same main was about to fall off. All run at more the two times the elevation.

All those things have been remedied along with a new Fuddle stall and lighter wheels (60 lbs less weight overall with thiner tires up front) So expecting atleast 102mph isnt out of the question, I would think. Sure HP will always help your trap speed, but so will freeing HP due to drivetrain loss (or problems) and lightening the car overall. That is why I thought 104-105mph was an acceptable trap speed.

I am gonna check my rockers, and install an air foil and see if it does anything at all for me. Im doubtful it will give me even a 1mph but heck I'll try anything. Perhaps your dead on, and I need to get a bottle to hit the 12's or 110mph. I was hoping to run in the 12's with no power adders, cams, or heads.

 

to get 12's with stock heads/cam/no power adders, u will need bigger stall, and at least 4.10 gears IMO. maybe weight reduction. your power is about right for your mods depending on conditions.

 

Stock springs will restrict your upper rpms because of float. It does no harm to put in better springs. Also with the addition of higher ratio RRs you get a more stable valve train, less friction and higher lift with a smidgen of duration. Something like this may get you some more power. A stock LS1 was rated at around 105 and they came out of the box with around 350 fwhp.

Weight reductions, drag reductions, parasitic engine and drive train reductions---all add up to maximizing the available power you have, but they do not increase your power. So there is no guarantee that doing somehing other than increasing the RWHP will get you any significant increase in mph.

BTW: You can't necessarily rely on someone elses ets, mph, etc to determine future results, since no two trials will be under the exact same conditions. JMHO

 

Did you have drag radials on? Was a shift kit installed? I would start with a valve adjustment, I mean you should probably be a tad faster for MPH with the mods you have. I would like to think a real high 12.99 is possible with your mods on the perfect day with a great launch! I didn't see an EWP in your list, that could be good for a few more hp!
Disconnect the belt as a last resort!

 

I have the same problem. I get great 0-50 and from 50-100 if feels like its not as good as it can be. I was trying to figure out how to tell if springs or rockers were my problem.

 

A bigger stall is definately not gonna help as it would put me right out of the stock cams power range. 2800, 300RPM stalls are a perfect match to a stock stall. I had my stall configured by John Camron at Fuddle Racing to match my car in its current configuration. He said that anything higher then a 3000RPM stall will push my car out of its power range. 4:10s will do the same thing, by having me run out of gear before I reach the quarter with the stock cam. If I had a hotcam or custom cam that would be true, but with a stock cam they wouldn't really help.



Yeah I was looking at some 1.6RRs new springs etc. I am sure my 158K LT1 could use a freshing of the valvetrain. It certainly wouldn't hurt it top side thats for sure. I am thinking it is capable of higher traps without having to buy all new vavletrain parts though. It may not be, and I maybe forced to buy new parts to make more HP to achieve 102+ mph traps.

You are right about compairing slips with someone else even if it is the same car. To many variables to be accurate.

Its just frustrating, I was really hoping for room to improve my ETs with simple adjustments and more practice. I hate to hit a wall after my first run with my new mods. I just dont see me improving my ETs with a 101mph trap. Seems I am tapped out without buying more parts...

 

Seems to me that you are half way there. You've got the first half won, you just need to get some more up top. With the stock cam and 3.42s you will be hard to beat off the line. With some topend stuff (at a min. some springs, and better yet, higher lift---if you don't do a cam right away) you should reach your immediate goals. JMHO

 

ehh, people have run 12's at 101 trap speeds. like 12.9's, but still 12's. car has to be completely set up for drag racing. my uncles 00 GT mustang traps 100.1 and he runs 12.9 with a 1.6 60 ft and i have personally seen it. has 4.56 gears in it/major suspension work. i'd say 4.56 is over geared for a bolt on car, but hes running 12's. If his mustang can do it, i'd say your car can...unless im missing a big difference between mustang and lt1 powerbands/gearing.

 

Yeah off the line I was cooking, I raced a 500+hp 300zxTT and he was toast to the 1/8th, but after that it was a WHOLE different story hehehe. I guess a valvetrain upgrade, and or Nitrous are in order. Sucks that I can't get my 12.9 goal without them though. Bubba you think a valve adjustment and TB Airfoil will net any results?


12.9 is my goal. Heck 12.9999 would be AWESOME!! I have to agree with you4.56 is pretty over geared for a bolt on car, unless its a 6sp (then its only a tiny bit over geared). I have a lot of suspension work already. Its not all the very best, but its a good bit. Here is a short list of my suspension mods:

Strano Revalved Bilstein HD Shocks
Eibach Pro-kit lowering springs
BMR Tubular Subframe Connectors
Prothane Motor Mounts
98+ Front Brakes
Lakewood Boxed Rear Control Arms
Lakewood adjustable panhard rod
SJM ABS Delete Kit, Line Lock, Wilwood Prop. Valve
Energy Suspension Poly Transmission Mount
Welded LCA Relocation Brackets
MOOG Front Lower Ball joints
MOOG Front Lower Control (A-Arm) bushings

As you can see its not exactly perfect for drag racing, but in place, and why I think I did cut 1.8 60's all day long. I dunno if I can run a better 60'. I was to chicken to drop the psi in my MT DR's to the recomended 16-12psi. I ran 23psi and it hooked very well for me from a 1400RPM flash. If I had a higher trap I would go for it and try and cut lower 60's but I dont think I have lower ETs in the car I dont even think I can run 13.2, 13.1 much less a 12.99999. I'll try again this Friday and see. I would assume that the car's you've seen run 12.9 with 100 & 101mph trap were very light. My Formula is light, but I dont think its that light.

Ok last question on this. In your opinion what are the top 3 mods I can do excluding cam, and heads to help my top end power. Obviously 1.6RRs, and springs would help any other suggestions?