how can i make my 86 GT run 12s???
- Thread starter ALLAN_M
- Start date
Jason 302
10 Year Member
Put some ported E7's or GT-40's on (probably have to flycut pistons, it's an 86), put a standard street cam in (E303, TFS #1), a aftermarket intake (Cobra, Edelbrock), with all the goodies (throttle body, underdrives, 4.10 gears), don't forget subframe connectors. Put some slicks on and launch the hell out off it!
Definitely a gear. Problem is the 86 has the EVER NO SO POPULAR E-6 heads which are very poor for performance upstairs. If you want 12's for an 86, I would take the sneaky route of concentrating on suspension. The motor itself (heads, intake) aren't going to cut it by itself. If you add too much of a gear on an 86, you will slow it down, because you will be busting out of its power range. The 86 has a VERY NARROW power range. Too much gear, and you won't be using any useable power the 86 has downstairs. You probably need to shift that thing at 4800. It will rev higher, but you ain't gonna be pulling anymore. Put a 87 -> upper intake on it. Can't change the heads too much as the pistons have no valve reliefs, unless you port some E-7's. This will give it GREAT compression and fool people. If you take this route, you can't change the cam as your P/V clearance will be close enough anyway......
Jason
Jason
Another option is a set of TFS heads, custom cam, aftermarket intake and exhaust, mass air conversion, and throttle body.
The TFS heads will allow you capitolize on extra compression provided by the 86 flat top pistons.
Then there is always the blower route. Centrifugal superchargers are not the best pick unless you change the heads. Just when you get up to the RPM where the blower starts making power, you run out of head (as suggested by 85mcLaren ).
The TFS heads will allow you capitolize on extra compression provided by the 86 flat top pistons.
Then there is always the blower route. Centrifugal superchargers are not the best pick unless you change the heads. Just when you get up to the RPM where the blower starts making power, you run out of head (as suggested by 85mcLaren ).
Modular2v said:
Not so. The arrangement of the valves on TFS heads give the clearance necessary for a decent cam over the top of the flat tops.
The rule of thumb for 86 flat tops and TFS heads is no more than 224* @ .050" dur, No less than 112* LSA,
You can go up to approximately .550" lift.
In a boosted applications, install the TFS # 31400414
dual springs. Set the installed height @ 1.780" for a seat pressure of
125lbs...
--or--
Get a TFS # 51400004 as it already
has the appropriate dual springs installed...
The guildelines above including the LSA also happen to be a very nice profile for a blower cam.
What Daggar says is true for most 86s. The TW heads will give better performace on the 86s due to the higher compression. But I will tell you the old 'cop-out' story and check the P/V clearance with any head (TW or E-7s) on an 86. The tolerances vary on every motor and on an 86, I would defenitely check......
Paul Perreca
New Member
- Mar 30, 2005
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Jason 302 said:
Is this true? (how bout mass air and A9L comp?) If that is true, than my 88 (after mass conv) with ported polished E7's, cobra upper and lower, 70mm throttle, 76mm C&L, e 303 cam, and 3.55s could possible run in 12's??? That would be bad ass - but just doesnt seem realistic. 12's is fast.
I don't think it would be 12s. Could be (maybe with correct suspension work). I don't think ported heads and a cam matched with only 3.55s is going to do it. Obviously some cars are better performers than others, but I just don't see it. Maybe low 13s, but that combo with correct suspension might get close. Factory 87-88s with correct suspension work 'back in the day' could run mid 13's, but some of them were 'factory freaks'.
Don't build a new house on a cracked foundation...
First of all I would check to be sure the near 20 year old motor is up to the task. Check compression and then leakdown. Often people keep modding worn out motors and it never performs right. Even if the engine is marginal, putting on higher end components is only going to increase the demise of the old motor. A used 87-92 bottome end usually is pretty cheap but for the price you can get a new basic 306 for a pretty low cost.
First of all I would check to be sure the near 20 year old motor is up to the task. Check compression and then leakdown. Often people keep modding worn out motors and it never performs right. Even if the engine is marginal, putting on higher end components is only going to increase the demise of the old motor. A used 87-92 bottome end usually is pretty cheap but for the price you can get a new basic 306 for a pretty low cost.
TW heads, 4.10 gears, an RPM intake and some sticky tires should put you into the 12s for sure.
on my stock motor and 4.10 gears, i was running 14.3, but at like 95mph. if i would have invested in some traction, it would have been like 13.7s @ 98 or so.
on my stock motor and 4.10 gears, i was running 14.3, but at like 95mph. if i would have invested in some traction, it would have been like 13.7s @ 98 or so.
25thmustang
Mustang Master
Paul Perreca said:
Its plenty true. My combo is stock bottem end, E7s with GT-40 valves, valve job, and rockers, Stock cam, Cobra intake, TB, MAF, LTs, full exhaust, and a stock suspension, with a stock T5 and runs mid 12s all day long. Flat tops might be worth a little more but I would say a high 12 is pretty attainable!
even a high 12 on street tires with that combo listed here could happen, but dont take my word for it!
Jason 302
10 Year Member
Paul Perreca said:
That's basically what I ran last year. I don't know if 3.55's would get you there, but for sure 4.10's. My combo last year.
306 (10:1), self ported E7's (stock valves), TFS #1 cam, Edelbrock Performer, 70 TB, 75 MAF, BBK long tubes, underdrives, electric fan, 3.73's, and M/T slicks. I launched at around 5200 rpm, and shifted the T5 hard. Ran a best of 12.898 @ 105.15 mph. 12's is fast, but is fairly easy to get these days.
