More VI track times, something's not right...
08-17-2002, 10:19 PM
#1
More VI track times, something's not right...
Took the Max to the track again Friday this time on my 17" Kosei K1s with 235-40-17 tires to see if a gearing change would help me, as with my normal drag wheels I'm banging the rev limiter in 3rd about 50 feet shy of the line and its hurting my times and speeds.
Well Friday turned out to be disastrous, I think something is now wrong with my car though I haven't a CLUE as to what it might be (description to follow).
Conditions were: 75-78 dropping to about 70 as the night went on, 65% humidity, 10mph or so headwind. Weather was nice for running though the wind certainly didn't help... how much of an effect would a 10mph headwind have on performance anyhow?
First run: VI RPM switch set at 4600rpm
2.201 60'
6.146 330'
9.377 1/8
76.65 mph 1/8
12.172 1000'
88.42 mph 1000'
14.528 1/4
95.49 mph 1/4
This run was my only clean run of the night, first run of the day, I had an ice bag on the VI for about 10 minutes prior to the run, but I don't feel the ice had any effect given the design of the VI and the fact that it wasn't that hot out anyway. The 235-40-17s allowed me to shift into 4th about 150' before the finish line.
2nd run: VI still set at 4600rpm
2.271 60'
6.249 330'
9.509 1/8
74.96 mph
12.310 1000'
87.39 mph 1000'
14.690 1/4
92.42 mph
This run I missed 4th gear and coasted across the finish line. BTW this is the first time I've ever missed a gear at the track (besides in Brian's car), and I've got about 120 passes under my belt, 100 in this car. No ice bag on the VI this time.
3rd run: VI set at 4800 RPM this time
2.294 60'
6.252 330
9.486 1/8
75.96 mph
12.262 1000'
88.20 mph 1000'
14.607 1/4
95.96 mph
This was my other clean run for the day, though the tires were still wet (cant get around the water and I didn't want to burn out in my $180/tire T1-S). Ice bag on the intake for 10 minutes or so prior to the run.
4th pass: VI set at 5000rpm, this is where the car shows signs of a problem.
2.295 60'
6.391 330'
9.736 1/8'
73.76mph-------> notice this speed... down 2mph from where it should be
12.643 1000'
84.73mph----> down about 3-3.5mph from where it normally is
15.092 1/4
92.16mph----> down about 4mph from where it should be.
This run, the car was completely cool, it had been sitting for 1.5 hours. The temp was down to about 70 at this time. No issues with the run other than a SLIGHT grind into 3rd gear, like I started releasing the clutch a fraction of a second too early. I was very worried at this point, checking for fluid leaking under the car, etc. Found none. Checked the operation of the VI by manually blipping the throttle under the hood, it was working as it should be. <baffled>
5th pass: VI at 5000, still something wrong, but not as severe?
2.228 60'
6.171 330'
9.433 1/8
76.15mph----> notice my 1/8 speed went back up to normal, good.
12.255 1000'
87.01mph----> oh crap, down about 1mph from where I should be
14.652 1/4
93.95mph----> up from the last run, but still down about 2-2.5mph
No major issues with this run, again a SLIGHT grind into 3rd gear, same as above. Checked operation of VI when back in the pits without shutting car off, operating as normal. WTF where did my power go up top?
I was in the staging lanes for 1 more run, hoping to see my car running normal again, but someone broke bigtime, and they called the rest of the night off. Damn. One thing I forgot to check was the wind later in the night, I didn't notice if it had picked up or not, maybe a stronger headwind killed me on the far end on the last 2 runs, they were mad about 35 minutes apart, but about 2-3 hours after my first 3 runs. I really wish I had gotten that final run in.
On the way home on the highway I was of course worried that I had done something to my car. On the highway, it didn't "feel" strong up top, but that could have been my imagination running wild and making things seem worse than they really were.
I plan on pulling apart my VI vacuum system this week to make sure my check valves and everything are operating as they are supposed to. Also going to check the torque on the IAC and TB bolts to make sure I've got no leaks.
Anyone have any comments, ideas, suggestions, etc?
Well Friday turned out to be disastrous, I think something is now wrong with my car though I haven't a CLUE as to what it might be (description to follow).
Conditions were: 75-78 dropping to about 70 as the night went on, 65% humidity, 10mph or so headwind. Weather was nice for running though the wind certainly didn't help... how much of an effect would a 10mph headwind have on performance anyhow?
First run: VI RPM switch set at 4600rpm
2.201 60'
6.146 330'
9.377 1/8
76.65 mph 1/8
12.172 1000'
88.42 mph 1000'
14.528 1/4
95.49 mph 1/4
This run was my only clean run of the night, first run of the day, I had an ice bag on the VI for about 10 minutes prior to the run, but I don't feel the ice had any effect given the design of the VI and the fact that it wasn't that hot out anyway. The 235-40-17s allowed me to shift into 4th about 150' before the finish line.
2nd run: VI still set at 4600rpm
2.271 60'
6.249 330'
9.509 1/8
74.96 mph
12.310 1000'
87.39 mph 1000'
14.690 1/4
92.42 mph
This run I missed 4th gear and coasted across the finish line. BTW this is the first time I've ever missed a gear at the track (besides in Brian's car), and I've got about 120 passes under my belt, 100 in this car. No ice bag on the VI this time.
3rd run: VI set at 4800 RPM this time
2.294 60'
6.252 330
9.486 1/8
75.96 mph
12.262 1000'
88.20 mph 1000'
14.607 1/4
95.96 mph
This was my other clean run for the day, though the tires were still wet (cant get around the water and I didn't want to burn out in my $180/tire T1-S). Ice bag on the intake for 10 minutes or so prior to the run.
4th pass: VI set at 5000rpm, this is where the car shows signs of a problem.
2.295 60'
6.391 330'
9.736 1/8'
73.76mph-------> notice this speed... down 2mph from where it should be
12.643 1000'
84.73mph----> down about 3-3.5mph from where it normally is
15.092 1/4
92.16mph----> down about 4mph from where it should be.
This run, the car was completely cool, it had been sitting for 1.5 hours. The temp was down to about 70 at this time. No issues with the run other than a SLIGHT grind into 3rd gear, like I started releasing the clutch a fraction of a second too early. I was very worried at this point, checking for fluid leaking under the car, etc. Found none. Checked the operation of the VI by manually blipping the throttle under the hood, it was working as it should be. <baffled>
5th pass: VI at 5000, still something wrong, but not as severe?
2.228 60'
6.171 330'
9.433 1/8
76.15mph----> notice my 1/8 speed went back up to normal, good.
12.255 1000'
87.01mph----> oh crap, down about 1mph from where I should be
14.652 1/4
93.95mph----> up from the last run, but still down about 2-2.5mph
No major issues with this run, again a SLIGHT grind into 3rd gear, same as above. Checked operation of VI when back in the pits without shutting car off, operating as normal. WTF where did my power go up top?
I was in the staging lanes for 1 more run, hoping to see my car running normal again, but someone broke bigtime, and they called the rest of the night off. Damn. One thing I forgot to check was the wind later in the night, I didn't notice if it had picked up or not, maybe a stronger headwind killed me on the far end on the last 2 runs, they were mad about 35 minutes apart, but about 2-3 hours after my first 3 runs. I really wish I had gotten that final run in.
On the way home on the highway I was of course worried that I had done something to my car. On the highway, it didn't "feel" strong up top, but that could have been my imagination running wild and making things seem worse than they really were.
I plan on pulling apart my VI vacuum system this week to make sure my check valves and everything are operating as they are supposed to. Also going to check the torque on the IAC and TB bolts to make sure I've got no leaks.
Anyone have any comments, ideas, suggestions, etc?
08-17-2002, 10:30 PM
#3
Originally posted by matty
14.528 isnt good ?? If it isnt, check the engine light...if you feel bad up top it may be your KS...14.5 sounds pretty solid but you know the car more than I do
-matt
14.528 isnt good ?? If it isnt, check the engine light...if you feel bad up top it may be your KS...14.5 sounds pretty solid but you know the car more than I do
-matt
I'll check for codes this week, my car pulls like 4 codes normally so my CEL is always on. Maybe its getting to be time for a knock sensor replacement.
Actually I'm not very happy with the 14.5, I've run 14.4s without my VI, albeit with a little lower trap speed. I'm still not convinced this thing is opening when I am at WOT... I'm going to rig my vacuum system this week so I can tell if there is vacuum going to the actuator valve when I'm at WOT. I've had a ***** of a time determining if my check valve is operating as its supposed to, and honestly I don't know if it is or not. It seems to be, but I'm not totally convinced from the tests I've done on them.
How many miles you have ??
08-17-2002, 11:17 PM
#6
Not DAVEB the parts guy
Join Date: Aug 2000
Posts: 8,555
You should be able to test the check valve on the tank by simply blowing in and out of the tank with your mouth on each hose.
I don't know what to tell you about your car's performance. I really doubt it's the VI because the VI manifold, when not operating, performs exactly like the stock manifold therefore you should be running your US-Spec manifold times.
I'll be going to the track this Wednesday. I'll you what though, I wish I could pull off 14.5s.
Dave
I don't know what to tell you about your car's performance. I really doubt it's the VI because the VI manifold, when not operating, performs exactly like the stock manifold therefore you should be running your US-Spec manifold times.
I'll be going to the track this Wednesday. I'll you what though, I wish I could pull off 14.5s.
Dave
08-18-2002, 09:55 AM
#10
Dave- I have an external check valve that I tested and when blowing in it with my mouth it worked, I even tested it with water to see if i could blow bubbles each way through it (with hose attached) and it worked, however when I attach it to the manifold vacuum, it allows air to flow either way, I think the vacuum is overpowering it.
There seems to be one built in to my vacuum canister, but its hard to describe why I can't quite tell whether its working or not. It almost seems like sometimes its working (i.e. only flowing one way) and sometimes its not (flowing both ways). I know that sounds rediculous but I was an aeronautical engineering major for 3.5 years and I know how to test stuff, and it seems that at different times I get different results.
Darksands, thats a good idea, but unfortunately I know thats not the problem, because last week I made all my runs with the VI set at 5000 and I ran just fine, 14.5s and 14.4s.
There seems to be one built in to my vacuum canister, but its hard to describe why I can't quite tell whether its working or not. It almost seems like sometimes its working (i.e. only flowing one way) and sometimes its not (flowing both ways). I know that sounds rediculous but I was an aeronautical engineering major for 3.5 years and I know how to test stuff, and it seems that at different times I get different results.
Darksands, thats a good idea, but unfortunately I know thats not the problem, because last week I made all my runs with the VI set at 5000 and I ran just fine, 14.5s and 14.4s.
08-18-2002, 03:48 PM
#11
If you are trying to test the integrity of your vacuum canister, try this:
After Idling your car for a minute or so, turn the car off. 1/2 hour later (or however long a time you deem sufficient), open your hood and go unplug the vacuum tubing going from your vacuum canister to the solenoid. You should hear a gush of air going into the canister. A tight system will store vacuum for quite some time! So at WOT, you definitely should have enough store vacuum if you pass this test.
I just redid my vacuum canister to another location. Am using the NAPA again but left the external check valve in place as security. Although it is easy to reverse a check valve, if it is reversed, the system wouldn't work at all. If the valve is incompetant, you will not get stored vacuum but the NAPA should serve as your security--it is unlikely that both are incompetant.
However, I'm thinking if you do the above vacuum storage test and it checks out, the VI should be working properly since it seems to work at idle with the throttle pull.
Small vacuum leaks may translate to performance loss: You may also a want to test manifold vacuum pressure on a guage or just have your car dyno'd.
After Idling your car for a minute or so, turn the car off. 1/2 hour later (or however long a time you deem sufficient), open your hood and go unplug the vacuum tubing going from your vacuum canister to the solenoid. You should hear a gush of air going into the canister. A tight system will store vacuum for quite some time! So at WOT, you definitely should have enough store vacuum if you pass this test.
I just redid my vacuum canister to another location. Am using the NAPA again but left the external check valve in place as security. Although it is easy to reverse a check valve, if it is reversed, the system wouldn't work at all. If the valve is incompetant, you will not get stored vacuum but the NAPA should serve as your security--it is unlikely that both are incompetant.
However, I'm thinking if you do the above vacuum storage test and it checks out, the VI should be working properly since it seems to work at idle with the throttle pull.
Small vacuum leaks may translate to performance loss: You may also a want to test manifold vacuum pressure on a guage or just have your car dyno'd.
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