Need help at lose of ideas down 6 mph
Thread Starter
TECH Apprentice
Joined: Dec 2011
Posts: 315
Likes: 0
From: toccoa ,ga
Need help at lose of ideas down 6 mph Put my old motor in my brother car.. Down 6 mph.
Motor went 7.237 @93 11.475@114 in my car at 3400. Put motor ,trans, stall ,headers, y pipe and tune in brother car been 7. 85@86 12.46@ 107. His weighs 3570.
My car had 3.73 his has 4.10. Which should help the diffence in weight.
We been fighting this a year now seem.
We have swap stall and trans 3600 to 4500 no help just 60' better. Checked fuel pressure 43 psi at wot. Changed plug wires. Running tr6 which are clean. I have changed tunes locked out timing etc no help. added/ pulled timing no help.changed map and tps. Which they look good in Logs. Nothing in logs coming up odd. Did leak down test come back normal. Compression test was good. We have swapped out opti few times. Valve lash is at 1/2 turn. Swap different Cold air intake no help
Oh motor info is
Ported head flow 260
Cam Le 228/236
Ported intake
Other normal stuff
In my car at same weight with cam only cc305 that motor went 7.79@ 87.
This car has made roughly 60 pass and stay the same.
Any help.. Please!! My brother so upset. I thought he was gonna cry other night he was so pissed at car.
Motor went 7.237 @93 11.475@114 in my car at 3400. Put motor ,trans, stall ,headers, y pipe and tune in brother car been 7. 85@86 12.46@ 107. His weighs 3570.
My car had 3.73 his has 4.10. Which should help the diffence in weight.
We been fighting this a year now seem.
We have swap stall and trans 3600 to 4500 no help just 60' better. Checked fuel pressure 43 psi at wot. Changed plug wires. Running tr6 which are clean. I have changed tunes locked out timing etc no help. added/ pulled timing no help.changed map and tps. Which they look good in Logs. Nothing in logs coming up odd. Did leak down test come back normal. Compression test was good. We have swapped out opti few times. Valve lash is at 1/2 turn. Swap different Cold air intake no help
Oh motor info is
Ported head flow 260
Cam Le 228/236
Ported intake
Other normal stuff
In my car at same weight with cam only cc305 that motor went 7.79@ 87.
This car has made roughly 60 pass and stay the same.
Any help.. Please!! My brother so upset. I thought he was gonna cry other night he was so pissed at car.
Were the cars ran in similar weather (DA)? How do the timeslip splits look, 60fts? If he went 107 and you went 114 but he is 170lbs heavier so drop off 2mph right there and the mph is only off by 5mph. If you ran in good weather and him in this crappy heat and humidity then a 5mph difference is not that bad especially if the car is heat soaked and you ran it in negative DA.
hmmm, wonder if it is running out of gear with the 4.11's? what do the timeslip splits look like comparing the 2 cars runs. That will tell you if you are losing acceleration at a certain point or across the board.
On The Tree
Joined: Jun 2015
Posts: 182
Likes: 3
From: Portland OR
If you improved the 60f times there should have been an overall improvement.
Given that my tinfoil hat opinion is something is wrecking the top end.
Exhaust
Fuel delivery
or it has a barn door strapped to the front of it
Given that my tinfoil hat opinion is something is wrecking the top end.
Exhaust
Fuel delivery
or it has a barn door strapped to the front of it
How do the 60ft's and 330fts compare? What wheels and tires are on your brother's car? If he is running a heavier rotating weight (17's on all 4 corners) and you were running skinnies and lightweight drag wheels that could make a .2 and 2 mph difference in times.
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Verdad Gallardo Thread Starter
TECH Apprentice
Joined: Dec 2011
Posts: 315
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From: toccoa ,ga
I run my wheels and tires on it. Still no help
Thread Starter
TECH Apprentice
Joined: Dec 2011
Posts: 315
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From: toccoa ,ga
May readjust valves. I'm pretty good tuning.. I got buddy I tune his bolt on car 3030lbs run 12.6@105 best mph was 109mph Friday night. Which really pissed my brother off.. Two transmission been tried. I checked brakes and even redo rearend check drag etc. fueling idk sixty down too..
Wow, this is a real stumper. 7mph is 70hp or so. That is a lot of difference. As other have stated. Dragging brakes, slipping trans? Are the shift points the same rpm? How does the car feel and run? Anything off or just not seem right? Misfires? Have you checked the spray on the fuel injectors?
Thread Starter
TECH Apprentice
Joined: Dec 2011
Posts: 315
Likes: 0
From: toccoa ,ga
It's got cheap opti at moment. I give him my msd unit but it had be sent back msd. Which should be back in tomorrow. I tried one those cheap ones my car went 8.0 at 87. I add some timing got it to 90 with that opti. My car normal mph 98 ish on motor. My car was opti eater 12 opti in last yrs so went to carb.
Thread Starter
TECH Apprentice
Joined: Dec 2011
Posts: 315
Likes: 0
From: toccoa ,ga
Wow, this is a real stumper. 7mph is 70hp or so. That is a lot of difference. As other have stated. Dragging brakes, slipping trans? Are the shift points the same rpm? How does the car feel and run? Anything off or just not seem right? Misfires? Have you checked the spray on the fuel injectors?
TECH Enthusiast
Joined: Jul 2007
Posts: 563
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From: Central,NJ
Since no one else mentioned it, weak valve springs.
The power falls off if the valve bounces. Compression and leak down check will not find this and for the most part, it will run fine.
Check spring pressure if you know what the installed seat and open pressures should be new and calculate percentage of loss, if not toss some fresh springs in it.
The power falls off if the valve bounces. Compression and leak down check will not find this and for the most part, it will run fine.
Check spring pressure if you know what the installed seat and open pressures should be new and calculate percentage of loss, if not toss some fresh springs in it.
