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Topic: Back from the track (Read 2223 times) previous topic - next topic

Back from the track

Went down and back without needing to call home for the trailer...so that's a win right there!!

Got four passes in.....there's some good and bad news.  I made three passes (#1, 2 and 4) and I let a friend drive the third pass.  It was running a set of 26x10.50-15 MT ET Streets on turbine wheels with 20# of air.  Should have dropped them to 13-ish but it slipped my mind.

Pass #1 was a 1.96 (60'), 14.1 @ 95.6 mph.

Pass #2 was a 1.95 (60'), 14.06 @ 96.5 mph.

Pass #3 was a 2.1 (60'), 14.31 @ 98.1 mph.

Pass #4 was a 1.91 (60'), 14.05 @ 96.6 mph.

The good news....I'm pleased.  There was a Lincoln spec'd out about the same as the 'bird (HO, T5) that was running high 14's and low 15's.  On my passes it was launched at 4,000 rpm and shifted at 5,800rpm.  The one down side is a dead flat spot at 4,800rpm. It pulled hard to 4,800, flattens out then pulls up to 5,800...this happens in each gear and I'm pulling into 4th about 100' before the traps (so three times).  This flat spot is costing me at least two tenths.  I had noticed this on the street also so I was aware of it before going down.  I'd be at least solid 13.75 car without the problem.....and I'm happy with that in a fully dressed Thunderbird running 3.55's.

Any ideas of what may be causing the problem??  Timing is 16 degrees, FP is 42#, MAF is stock, TB is 70mm Edelbrock, intake is Explorer.

Just throw some ideas out and I'll start tuning.
1988 T-Bird Sport Coupe--5.0 HO, MAF swap, 1-5/8" shorties, BBK/Flowmaster exhaust, Explorer intake, 70mm Edelbrock TB, T5, B&M short throw, Centerforce clutch and PP, disc brake TC rear w/ 3.55's, TC front brakes, '98 Cobra springs, DIY SFC's, other misc .  14.05 @ 98mph with launching too low and shifting too high.

Back from the track

Reply #1 –
Looks like you had a good time. The car seems to be running good too. That would've been cool to have been there to see it and video it.

Back from the track

Reply #2 –
Bottom 14's with a primarily stock H/O is doing well! 

If the H/O is stock except for the intake & T/body, you might want to try short shifting at 4,800-5,000.  Taking a trip in the "way back machine" to the late '80's, stock Mustangs ran their best times shifting under 5k.  They may rev higher, but there isn't much power to be had.  Even a good H/C/I with a free flowing exhaust (assuming a long runner intake) is typically all done with a shift point of 5,800.

The great part about trying it is: Might be the cheapest and easiest "fix" to get you into the 13's!

A tip to try at the dragstrip is: "locking the timing out".  You do this by pulling the sprout (and leaving it out) and setting the total timing (if you are running 16 degrees now, that would be ~36 degrees with the sprout left out).  Then make some runs, advancing and retarding it to find your max MPH.  The extra timing off the line might improve your 60' too.

Keep having fun!

Back from the track

Reply #3 –
Quote from: 86T-bird;392405
Bottom 14's with a primarily stock H/O is doing well! 

The long block was never cracked open other than to swap the intake....and I want to leave it that way.  The only swap I'd do would be to go with a full Explorer "P" motor but that's not even in the forecasted future.  It's even running a full length belt, spinning all the accessories and running a clutch fan.  I had short shifted on the street and it still pulls strong but tough to tell if its any quicker...so that will surely be the main thing to test next time.

About the timing....you are saying to set the total timing (with spout connector removed) at idle??
1988 T-Bird Sport Coupe--5.0 HO, MAF swap, 1-5/8" shorties, BBK/Flowmaster exhaust, Explorer intake, 70mm Edelbrock TB, T5, B&M short throw, Centerforce clutch and PP, disc brake TC rear w/ 3.55's, TC front brakes, '98 Cobra springs, DIY SFC's, other misc .  14.05 @ 98mph with launching too low and shifting too high.

Back from the track

Reply #4 –
Quote from: Dan B.;392408
  About the timing....you are saying to set the total timing (with spout connector removed) at idle??

 
Yep.

Starting with full advance is typically not an issue, as the compression on a stock motor is relatively low.  Expect it to idle faster though.

Quote from: Dan B.;392408
  It's even running a full length belt, spinning all the accessories and running a clutch fan. 

 
You've still got of few of the old trick to pull yet!  The short belt is often worth a .1.  A Taurus fan will help too.  Shopped right: $50 total.

Back from the track

Reply #5 –
My HO swapped bird has the same flat spot at the about same RPM (4800-5000).  I always figured that's just where its done making power due to the restrictive stock heads and intake, but I agree it is VERY noticable.  I've never been on the track but always shift around 5k because, as Mark pointed out, anything above that and the motor is really not making any HP.

That's very encouraging though if you are running low 14's on a stock-ish 302 HO.  I need to take my car to the local 1/8 mile track and see what it is capable of.
'88 'bird, 10.9:1 306 w/TFS top end, forged rods/pistons, T-5 swap & bunch of other stuff, 1-family owned, had it since ‘98, 5.0tbrd88 on Instagram and YouTube

Back from the track

Reply #6 –
Really good numbers 86!!!

Would a different MAF help?  I'm running the C&L 73mm on my 92 Mustang with stock TB and intake. The car is putting down 212rwhp with ALL accessories (including smog pump and clutch fan) and stock exhaust.  HO Engine has never been cracked.

I do have the timing advanced to 14 deg BTDC, 3/8" phenolic intake spacer, underdrive crank pulley, K&N air filter (in the airbox) with silencer removed, and adjustable fuel pressure regulator.

If I remember right, the stock MAF has the restrictive screen in it too.  You might try it without?

Back from the track

Reply #7 –
is the rear stock? any aftermarket suspension on the car?
 

Back from the track

Reply #8 –
TC rear w/ 3.55's and discs.  Otherwise all stock.
1988 T-Bird Sport Coupe--5.0 HO, MAF swap, 1-5/8" shorties, BBK/Flowmaster exhaust, Explorer intake, 70mm Edelbrock TB, T5, B&M short throw, Centerforce clutch and PP, disc brake TC rear w/ 3.55's, TC front brakes, '98 Cobra springs, DIY SFC's, other misc .  14.05 @ 98mph with launching too low and shifting too high.