[Jason Weaver]

Hey guys, give me some feedback on this run.

60' 2.14
1/8 8.66 86.5 mph
1/4 13.22 106.5

1993.5 auto - downpipe, exhaust, 5/16" bleeder T, BCC

trac fuse out, air filter in (not dirty), headlight in, built boost at the line....all stock excpet for mods mentioned....78 degrees..Rockingham, NC (not far off sea level)...93 octane pump gas ~17-18 lbs boost

Isn't the 1/4 mph way off? What would be causing this lack of mph at BPU - I would assume the absence of a filter or intake would not make this kind of difference. Not missing or no noticeable detonation. Thanks for any info or feedback guys.

 

[Scott]

Yeah the MPH is low. My first guesses are spark plugs or boost leak.

 

[KJSUPRA]

I would say boost leak most likely or plugs as well. I have the same mods as you on my 94 automatic and I just ran a 12.64 at 117mph. Good luck finding your problem and let us know what you find out...

 

[CBDFLY]

same car, same mods, same time, this weekend - i cannot stand it anymore!!!:ak:

 

[BPUed]

try running a little race fuel and reset the ecu between runs. If you bought some bad gas at one time in your cars life and never reset the ecu after then your time is retarded probably far enough to cause you times to be really off. You still could have a boost leak, but unless it's sizeable, shouldn't throw you off that much in my experience.

Jesse

 

[NatterDSM]

Buschur exhaust
Greddy BCC
hallman @ 17psi
new plugs
93 octane
94TT Auto
80deg track runs yesterday

I ran a 13.453 @107.95 on the first pass with a 2.143 60ft and never managed to getting anything better the rest of the afternoon. Every run I made was pretty much the exact same time and MPH. I'll give it that much it was consistant. My car was a turd till the second turbo kicked in even when building 10lbs on the line with the first. It wouldnt even spin the tires on a full throttle brake stand launch. For the life of me I couldn't get anything better than a 2.1 60ft out of the thing.

Needless to say I am a little dissapointed also. I'll be doing an intake pressure test sometime this week.

 

[BPUed]

Do you have a downpipe Natter? If not get one real fast you'll dip into the 12's pretty easy with that 60' time. I can't do anybetter then that 60' with my car and I've ran a [email protected]

93.5 Auto TT
HKS Ti exhaust
Custom 3.5" DP
Blitz SUS Power intake
Blitz SBC-iD
FFCD
12v Fuel Pump mod
EGR mod(Still need block off plate)

 

[NatterDSM]

Do you have a downpipe Natter? If not get one real fast you'll dip into the 12's pretty easy with that 60' time. I can't do anybetter then that 60' with my car and I've ran a [email protected]

Buschurs Exhaust is a 3.5 inch turbo back. What specific octane and boost were you running to get that time and mph? Thanks

 

[Jason Weaver]

Hey guys, thanks for all the responses. This is a great list. I recently had ngk 3330's put in the car and the gap was checked so I know the plugs are ok. I was getting a little miss and the plugs cured that. However, I just had to put a new battery in the car so the ecu may have already been reset. (the battery was replaced after the plugs). Maybe that was the problem again. I guess a boost leak is what we need to look for now. If I recall right we did not put a gasket on the turbo/downpipe connection so I might not be getting a good seal there. The Tanabe did not come w/that one (or it was supposed to go there vs on the connection to the exhaust). I would imgaine this could cause enough leak to make a difference??? I will get under the car and see what's up. Other than that which sticks out in my mind where else should I look for boost leaks? Again, thanks for all the help guys, and now that I think about it the missing gasket may be the problem. Any feedback is greatly appreciated.

 

[BPUed]

I was using a race gas/pump gas mix.

About 5 gallons of race gas, and ~2 gallons of 91 pump. Reset the ecu between runs, headlight in. Trac fuse pulled. I ran a 12.70 on 17.5 psi of pressure. I then turned up the boost to 20psi and discovered a boost leak above 19.0 psi, so I was unable to better my time. I have a feeling though I could get a 12.5 with my 60' times on the 20.0psi setting. Hopefully I can get that fixed for the winter. I run consitent high 12.0's with traps anywhere from 114mph to 116mph.

I was able to get a 12.8 this summer at 95 degrees. These runs were with outside air temp at about 65-75 degrees

 

[Josh S]

Hey guys, thanks for all the responses. This is a great list. I recently had ngk 3330's put in the car and the gap was checked so I know the plugs are ok. I was getting a little miss and the plugs cured that. However, I just had to put a new battery in the car so the ecu may have already been reset. (the battery was replaced after the plugs). Maybe that was the problem again. I guess a boost leak is what we need to look for now. If I recall right we did not put a gasket on the turbo/downpipe connection so I might not be getting a good seal there. The Tanabe did not come w/that one (or it was supposed to go there vs on the connection to the exhaust). I would imgaine this could cause enough leak to make a difference??? I will get under the car and see what's up. Other than that which sticks out in my mind where else should I look for boost leaks? Again, thanks for all the help guys, and now that I think about it the missing gasket may be the problem. Any feedback is greatly appreciated.

The missing gasket on the DP won't cause a boost leak, but you might have a small exhaust leak. I have my DP on without the gasket also and I don't seem to have any problems, I don't think a small exhaust leak with do anything at all.

 

[MKIVBADGER]

Something definitely seems off. For an additional reference, I posted the following times this last weekend:

60' 2.07
330 5.566
1/8 8.324
mph 89.65
1000 10.705
1/4 12.71
mph 111.7

Track conditions - 59F w/ 10-15 mph headwind
Car:
97 TT Auto
RMM DP
HKS Super Dragger Exhaust
GReddy BCC
K&N Drop in Filter
Profec B - 1.25 Kg/cm2
Pump Gas
Trac Fuse Pulled
ECU Reset
Stock Plugs
lst time at track

Jim

 

[deavenly1]

Yeah, something off, I run con. 12.5 at bpu+on mix race +91 and I can't build 10lbs. of boost off line. Tire's break loose at 7lbs.

 

[nito822]

Jason,

I would definetely do a pressure test on the system. Sounds to me like you have a boost leak or were getting timing cut. I don't think an exhaust leak would effect your times that much other than making an annoying noise.

BTW, what happened to the NSX (weren't you at the F&F car show in Cary)?

 

[Jason Weaver]

Ben, I still have the yellow nsx, and yes I was there at the show with the car. This is my brother's red 93.5. Tryin to get it all dialed in. I'm gonna see if we can come up w/something, I'm thinking it has to be a boost leak. Know of anyone good w/the supras around here that can do a pressure test? I have someone in mind but, just curious. thanks.

 

[nito822]

double post got click happy

 

[nito822]

I haven't had any work done on my car yet. I have done all the mods and maintenance myself.

I'm not real sure who can pressure test the intake. I made one for my eclipse back when I had it but didnt really have a good source of air as I dont have an air compressor. If you have an air compressor or access to one, you can just rig up a fitting to go where your intake is-or you can take that off and just put the fitting directly onto the hard metal pipe the plastic intake pipe attaches to.

Dont know if that made sense but basically you just want an airtight seal on the intake side and the ability to pump air into it. I rigged mine on my eclipse with a rubber 3" pipe? fitting but it would only hold around 13psi.

Where did you plan to take it? I can ask around for you with the DSM guys if they know of somewhere to get it done.

Let me know what you come up with....and who does the work. I'd appreciate it.

Ben

 

[Jason Weaver]

Ben, We got the car looked at today by Barry McCaskill here in Raleigh. He builds Toyota round track cars as well as a mechanic for a late model sportsman car at Orange county. He did alot of work on my white supra before I got the NSX. He did a smoke test through the intake system and we could not come up with anything. I understand this is not the same as pressurizing the system but he said he did not have anything availible that could do that, etc. We both looked for any cracked hoses or anything that looked off as well. I guess we will try resetting the ecu at the track next time on some higher octane fuel and see how it runs. Let me know if you have someone in mind for the pressure test on the intake. Ever go to the 1/8 track in Benson? Talk to ya soon.

 

[billvp]

you said that you had ~17-18 psi and then people said boost leak???

If you had an aftermarket gauge that said you were holding ~17-18 psi, then how would you have a boost leak??

 

[BPUed]

You could have a boost leak that prevents the wastegate from building enough boost. In my setup I have boost leak that doesn't rear it's ugly head until about 19 psi. I Then immediately drop to 17.5 psi and hold there. The pressure at 17.5 isn't high enough to cause this leak.