Is 112.3 mph low for, for 11.8 run??

[Thunder]

Just like it says... Just wondering if i should have more mph?? Best run was:
60' - 1.659 4psi launch
1/8 - 7.486 @ 91.37
1/4 - 11.811 @ 112.38

mph gain in last 1/8 only 21 mph.

Also in checking my ds logs I see
Launch rpm 3800 before mph hits 1
1st to 2nd shift from 5550 rpm, down to 4725 rpm... only 825 drop??
2nd to 3rd shift from 5200 rpm, down to 4600 rpm... only 600 drop??
Rpm crossing line ~5300-5400

tires were bfg drag radial 275/50... worn

anyone wants to look at ds runs let me know, and i'll mail em out

Thanks
Mike

 

[turbot2112]

that looks about right.my last run was a 12.4 at 111. my 60 ft was a 1.9.your 60 ft. is 3 tenths better which is 6 tenths quicker in et.

 

[Maltman]

I have slightly smaller diameter tires making top speed a little slower...does that apply to you? I'm using 255/50/16 bfg dr....but it looks like our ets/mph are close

1 of my 2 "11s" runs was:
1.72 60' @ 4-5 psi launch,
1/8 7.641 @ 90.54
1/4 11.971 @ 112.81

hth

 

[JDSfastGN]

Sounds about right, how much boost and timing were you running? 21 mph is close to what you should gain if your not locking the TC at WOT. Are you locking it? Is your 2-3 shift slipping or flaring at all? Just curious. I think a switch to 28" tall tires may give ya a mph or so

 

[Thunder]

My tires are kinda short... as they sit with 28psi in them measuring floor to top of tire is ~ 25 1/4. Probably has a bit to do with the high rpm/low mph issue.

The TC was locked (although it is single disc).

How do those rpm drops on the shifts look?? was wondering if the TC is too loose??

tia
Mike

 

[Thunder]

ttt

 

[Nocooler]

If you are truely turning 53-5400 threw the traps with the convertor locked - I'd say the transmission is slipping.

FWIW I cross the line @ 5300 @ 118mph with the TC locked on 275/50/15 BFG Drag Radials.

Jeremy

 

[UNGN]

Nitto 275/50's are 3/8" or so shorter than BFG DR 275/50's (25.6 worn to 26.0 worn). The most MPH I could EVER get out of BFG 275/50's was 113.96.

This was locked up D5 with a tight transmission

(25.6/26.0)*113.96 = 112.2 mph <= theoretically the Fastest my car could go using Nitto 275/50's.

Does anybody else see why I hate 275/50's with a stock motor?

Note that a 112.8 is in the ballpark.

 

[XLR8]

I ran an 11.56 at 113.0 with a 1.56 60' on 27" tires and I gained between 20 & 21 mph on that run.

 

[KEVINS]

I'll stir the pot and say no that does NOT look correct. You have a crappy 60' time (1.65) and a low mph (112) but a real good ET.. IMO you are making good midrange power but losing power on the top end.
11.8s should be closer to a mid/low 1.5 60' time and 115-116mph.
If you had a good 60' time (mid 1.5) then I can see the car just running out of steam but IMO there is somethign else going on here that is not correct.


ks

 

[UNGN]

Horsepower falls off a cliff above 5000 RPM with the stock motor. By 5500, it's probably making less than 1/2 the torque it makes at 4400 RPM (approximate HP peak for a stock motor). My car noses over at 5200 RPM.

The rate of Accelleration slows WAYYYYY down above 5000-5100 RPM. You are gaining 21 mph in the last 1/8 but probably only a couple mph in the last 200 hundred feet, instead of 5+

Switch to 28" tall tires and you will be over 115.

My first 11 was an 11.92@111, using 26" tall 275/50's.

I ran an almost identical run to yours with 28" tires:

1.65, 7.47@91.8, 11.83@111.5 when I was letting off before the traps so they wouldn't throw me out for running faster than 11.99. oops.

 

[Sweet6]

I have a car with a similar build to Thunders' and my car ran similar numbers on 26X10 ET Drags. I went to a 275/60 BFG and the car slowed down 2 MPH. I put on the 26X10 ET Drags and the car picked up 2 MPH. 60' were similar. So I am not sold on the 28" tire yet. FWIW I have hit 117.5 MPH on a stock motor with 26X10 ET Drags and unlocked converter.

 

[Thunder]

Well, maybe I'm paranoid, but I'm still wondering about that rpm after the shifts... staying in the 46-4700 range.. Is this normal?? I would have thought the rpm would drop a bit lower. The trans is a fresh rebuild (Jimmy's, in Mundelien, IL) beginning of 03. Maybe 1500 miles, and 15 track passes on it. I'm thinking the TC may need a restall... any opinions??

As far as the tires go, I will find out next time at the track if the 28's will help me. (maybe not till next year though) I am picking up a set of MT radials 275/60's. I know I am way out of the powerband, at the traps, and they have to help some.

Also someone asked about boost, timing etc. Timing was 18 deg, because I was running 93 and alky, boost was 26 psi, and o2 ~760, egt 1670. Maybe there is a few mph in race gas, and higher timing??

Thanks
Mike

 

[JDSfastGN]

I think your rpm drop is about right, 800-900 is what ive heard but i may let an expert confirm it for me. The 600 seems a little low on the 2-3. Are you locking the TC in 2nd gear? I don't like that as it seems to bog for me, i lock it at 85 and gained a solid 2 mph.

 

[Thunder]

I lock the converter manually, a couple secs after the 2-3 shift... Checked the DS log, and it looks like I'm hitting the switch about 83 mph.

 

[Sweet6]

Thunder,
I will sell you my half treaded 275/60 BFG DRs if you want. I am not that far from you either.

 

[shawnz]

Isnt 1675 egts kind of high.I was 1620 egt with 116 vp and no knock and could only muster 107 mph

 

[Sweet6]

I just ran 1690 on 110 without any knock. I usually go 1750 with 116.