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GARBAGE 1/4 mile times......

Tyler_Krupa

New member
Joined
Dec 7, 2012
Location
Southern N.H.
So I just went to the drags for the first time with my 940 and saying I'm disappointing is a little bit of an under statement.

My best slip out of the 3 I had time for was

R/T .293
60' 2.946
330 7.562
1/8 11.261@66.97
1000' 14.456
1/4 17.170 @ 83.56

I know I should be much faster than this. I tried one time with 2 step and once with brake boosting and those times were 17.197 and 17.226 respectively.

So far I have for performance mods,

15g flat flange
ported 90+
GFB electronic boost controller which is set to a duty cycle of 70 which is around 16psi with my wastegate
RSI stage 1 cam (1st gen)
Nuke cam gear set to 2 degrees advanced
TLAO Chips
Buchka Spark
3" downpipe to OBX 2.5" exhaust (no cat)
Accumulator mod
94 940 NA rear axle 4.10 in a 1041
So what I'm wondering is what should I take a look at that might be the problem. There is another street night Wednesday which I will be going to assuming I fix something.

So you don't have to read everything so far I have:
Pressure tested IC iping (no leaks)
Pressure tested whole intake (air leaking out charcoal canister lines, replaced and ziptied)
Verified timing belt was installed properly
Shimmed WG to make 8psi (had no pretension and only made 5psi)
Compression check (cyl1:140 cyl2:145 cyl3:150 cyl4:165)
Replaced blown out felpro exhaust manifold gaskets with elrings
Cleaned airfilter and MAF
Checked spark plug gaps and adjusted all to .28 (was .34)
Changed Diff fluid
Fixed valve lash, 2 intake were too loose and one exhaust was too tight.
Replaced crank position sensor with known good (was a little melted with exposed wires)
Replaced brake booster hose(had small cracks)
 
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How much boost is showing on your boost gauge?

And do you have a wideband and if so, what kind of reading are you getting at full boost?
 
honestly wasn't paying attention to ether, I take it for a drive and report back.

Edit:
12.6psi @ 11.9afr

Going to up the duty cycle a bit and see what happens. I feel like 75 out of 100 should be higher than 12.6psi with the stock WG. Last fall 75 was getting me 18psi
 
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The hot cam and an auto trans certainly ain't helping. It doesn't come on til fairly high RPM's and dialing back in some of your low end power with the cam gear doesn't get it all back.

Got a big intercooler?

And.... More boost!
 
your problems start with your 2.9 60' time and end with the 83mph trap speed.

loosely translated, you're not making any power, in fact.. you may owe power (Sorry, I'm being frank, not trying to be a smartass or rude)

on paper you've got the hardware to make things happen, and properly running that setup should easily put you off in the 14's.

I would do things in this order (and I'd do them all):
Reset the cam to zero degrees, verify mechanical timing. A stage 1 cam isn't wild enough to suffer behind an auto, so forget that post right off the bat.

Then I would make a boost leak tester, and check for boost leaks. you can do a smoke machine if you want, I've had good luck with an air compressor, some couplers and tastefully modified pvc caps. you can use a lowe's rubber pipe cap on the exhaust for that optimal seal, but I wouldn't worry much about leaks in the exhaust past the o2 sensor.

Then I would go about getting the boost up to 15-16psi and see how the car behaves. Depending on results, I'd either keep going up on the boost until it ran out of fuel (or knock resistance), or fudge with the cam a little.
 
upped the duty cycle to 88 out of 100 and got 16psi at 11ish afr.

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Not sure of timing or compression as I don't have a timing light or compression tester. I'll see if anyone I know had a timing light tomorrow after work.

linux nothing is coming off as rude, you guys know way more about this stuff than I do, Ill try all your stuff tomorrow I bought a pvc cap and compressor valve to make a leak teaster but never got around to making it.

I think getting beat by a 16.6 second stock mid 90s Honda accord was a bigger insult than anyone here can dish out.
 
I think getting beat by a 16.6 second stock mid 90s Honda accord was a bigger insult than anyone here can dish out.

We'll try harder.

Verify ignition timing and that the curve makes sense.

Verify that exhaust isn't a restriction.

What are intake air temps? More intercooler does wonders.
 
upped the duty cycle to 88 out of 100 and got 16psi at 11ish afr.

<iframe width="640" height="480" src="//www.youtube.com/embed/Yl0n5JU-gZw" frameborder="0" allowfullscreenghost ase></iframe>

Not sure of performance timing or compression as I don't have a timing light or compression tester. I'll see if anyone I know had a timing light tomorrow after work.

linux nothing is coming off as rude, you guys know way more about this stuff than I do, Ill try all your stuff tomorrow I bought a pvc cap and compressor valve to make a leak teaster but never got around to making it.

I think getting beat by a 16.6 second stock mid 90s Honda accord was a bigger insult than anyone here can dish out.

Man, I feel for you. If you have a auto parts store like Autozone you can rent a compression tester for free. You have to pay for on your credit card and they refund you when you give it back. I purchaced a boost tester from modern performance my Srt4 Neon and luckily it fit my Volvo. I want to see you get it sorted out. I'll be running later today and with yourset up your set up even with your larger car should be as quick or quicker than I.
 
Linuxman got it, it sounds more than likely cam timing is off. Could be a boost leak but it would have to be a pretty damn big one to cause that much of a loss. That doesnt mean dont boost leak test it. Also im only assuming you have done stage 0, correct?
 
ya with 16 psi on a 15g with those mods wheel spin off the line should be a problem. you should be making about 10 - 15 psi on the foot brake before the launch. if you have traction your 60 ft should be a 1.8 with good street tires to a 2.2 on bad ones. and that should net you a LOW 14 maybe high 13 if you get it to hook.
 
Where is boost threshold? That will tell quickly if its timing or a hurt motor.

Also listening to your video something doesnt sound good. I hear ticking almost like a pre turbo exhaust leak. Boost seems to come on late too strengthening my sneaky suspicion of cam timing off
 
seems like timing might be off a tooth judging by when boost actually hits hard (3800-ish?) and do something to improve those craptastic 60' times....a tenth in 60' is usually good for 2 tenths in the whole 1/4 mile (sort of a rule of thumb)
 
Are you brake boosting it at the line? Do you build boost if you do it?

ya with 16 psi on a 15g with those mods wheel spin off the line should be a problem. you should be making about 10 - 15 psi on the foot brake before the launch. if you have traction your 60 ft should be a 1.8 with good street tires to a 2.2 on bad ones. and that should net you a LOW 14 maybe high 13 if you get it to hook.

Brake boosting is a bit or a problem with my synapse synchronic BOV as it vents at idle. Best I can get is 0.0psi to 0.5psi until my tires spin. I have the anti stall kit for it which is horrible, basically it blocks the end of the bov with a plate on a spring that is designed to only vent when it blows off, not at idle. problem is that it doesnt vent at anything less than 6psi and just causes crazy turbo flutter. With this I can build all of 1psi of boost then my tires spin.

I'm waiting for the glue to dry on my pressure tester then I will check for leaks. I also just picked up a compresion tester from autozone and will be getting a timing light from my grandfather later today. I'll report back when I have done those tests.
 
My guess, is that there is a stage 0 related problem somewhere, vaccum line mis routed timing off. Go double / triple check all the normal every day stuff.

Also what size / type tires are you running? 1psi shouldn't spin them, you might need to try stepping on the brakes even harder to get her to hold on the line.
 
Just checked the timing with a timing light (cam set back to zero) the mark on the pulley was lining up with the right most line out of the three lines that are on the lower timing belt cover(not the line that is by its self to the far right. I'm assuming it should be lined up with the taller middle line. I know I can check the marks on the crank to the engine block but would rather not take the belts and covers off if my belt isn't off a tooth. Belt has come off three times in the past few months between checking for shim size, installing the RSI cam and then installing the nuke gear so I wouldn't be supplied if I put it on wrong one of those times without noticing.

Disregard my brake boost attempt, I tried it on my gravel driveway......:oops:

My tires are 215/45/17 Yokohama S-Drives
 
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