Problems Solved......mostly

[5150DSM]

To start off, for all of you who haven't figured it out, I'm stupid. I have had this exemplified to the fullest degree in my tuning endeavors. Ignorance for me however, was not bliss, It was hell. I kept thinking I knew but I never really did. So a thought occured to me; if I have no boost leaks, my injectors, pump, fpr, etc... are all installed properly, all of my sensors are operating correctly, all my maitenence has been performed and I have gone back to as close to stock as I can be, why does my car still run like ass? Hmmm... what about fuel pressure, I bet if the base pressure was too low, I would start running lean as I went into boost, which would make me knock and also be untunable because I was flowing much more air then fuel (skewed 1:1 ratio) So, with pliers in hand I checked my fuel pressure, what do you know... 34psi with the hose off, hmmm... 4psi off, I bet that really fu(ks with things. Made the adjustment to 38psi, went out driving for about an hour, part throttle, full throttle, 16psi on pump and 0 knock, averaging 20-22* of advance, I guess that was it. I'll know for sure after I run at the track again but I feel confident that my "weird" tuning issues are over and I can get down to the nitty gritty.(speed and power) Thanks to everyone who has thrown out ideas and helped me troubleshoot my stupidity. Now that my retardedness has worn off, maybe we can get some real numbers outta this beast.
On a different note, how do I get my trap speeds higher? I am seeing 96mph(as of tonight) at 7200 rpm in 3rd. I did start knocking badly at 6600 where my timing got yanked but I still don't think I would have seen 100+ mph by the same rpm had I not been knocking. Also, what is the factory rev limit for 1G AWD cars; mine will rev to 8k+ if I let it.(which I don't, on purpose anyway) My mph will keep climbing past 7k as well but I never get over 7200 on the strip(unless I hit a 20psi spike). Any info and/or experiences in this regard are appreciated.

 

[90AWDTalon]

On a different note, how do I get my trap speeds higher? I am seeing 96mph(as of tonight) at 7200 rpm in 3rd.

Your clutch could be slipping, on my stock clutch I would trap 97mph at 7500 rpms in third gear. After upgrading my clutch I trapped just over 100mph at 7500 rpms in third gear.

 

[5150DSM]

I have a fairly new Exedy 2100lb, I can barely get it to slip off the line but I will double check the disc next time we have the tranny down. Thanks, I wasn't headed that direction but its good to rule out all possibilities.

 

[90AWDTalon]

I had no idea my clutch was slipping until I went to the track with the new clutch and saw the faster trap speed.

 

[5150DSM]

Ok, so my fuel trims have leveled off finally(and permanently, I hope)my low is 104% and both my mid and HI are 100% and have been for several(4) days now. My injectors had started maxing out up top so I bumbed the base fuel pressure up to 43psi and reset the SAFC to 0% correction and turned down the boost. Result... I dropped my IJDC from 101% to 87%(at WOT), my fuel trims leveled off and my knock disappeared. I was only able to get in 2 runs at the track but my logs were stable and the car felt good. Unfortunately, my times still sucked, I only trapped 92mph in 3rd gear at 7100rpm and ran low 15's. I'm not so worried about the e.t's they will come down as I learn to drive the car but what's with the crappy trap speed? I figured once my car was tuned decently I would be able to trap 100+ mph, my horrible 60ft times are hurting me but I don't bog, I just down launch very hard. I can't really up the boost much, because the 550's don't have much left to give(I guess my car is runs leaner than most) Any ideas? For reference: 255 pump, AFPR@43psi, 550's, unhacked 1G MAF, SAFC-II, exhaust, intake, UICP, K&N open aircan.

 

[kpt4321]

With a 14b car with stock injectors, I was able to run a best trap of 102 mph. That's a full weight 93, on pump gas, with only a clutch, full exhaust, and intake pipe.

You definately have a power production problem.

Second of all, I would advise against going to 7100 rpm at the track, it's just not worth it with stock cams and the 14b. Try shifting around 6500 to see what hapens.

Factory rev limiter is 7500 rpm, and since the tach reads high it may "look" more like 8000.

You probably want to hack up the 1g MAF, at least a little bit. I am VERY surprised you haven't run into MAF overrun issues yet. Pull the lower honeycomb out, and back the screw out. Since you have a SAFC, you could do a little grinding too, but I would take it one step at a time.

 

[kpt4321]

What do your timeslips look like? Post one up here.

I want to have some information to compare to, in terms of trap speed, 60 foot times, and speed gain between the 8th and quarter.

 

[CanadianTSi]

Also, how much boost are you running?

 

[5150DSM]

Ok, so I originally had the MAF hacked but I was unable to tune it that way so I went back to stock. As far as RPM, I based the 8K number on my logger reading as opposed to the tachometer. MAF overrun, I am surprised as well, I have never hit anything resembling fuel cut, even off of a few random 20psi spikes. For this particular time slip(last night) I was running 92 pump at 12psi creeping to 15psi. Outside air was 72* and about 50% humidity. Launched at 4968, 1-2 shift at 6531, 2-3 shift at 7062, ran it out to 7062, 0 knock and 18-21* of timing throughout the run.

RT- 1.226
60ft- 2.322
1/8- 10.247
1/8- 68.89
1/4- 15.260
1/4- 90.93

 

[5150DSM]

A couple of quick questions to add to the rest... Is there any way to test the fuel pressure solenoid to see if it is working properly? Would a faulty FPS cause erratic behavior with the fuel/timing curves. Is the FPS something I should just bypass and if so, what would the overall effect be. Thanks for the help guys. I'm getting there, slowly, but I am getting there.

 

[kpt4321]

Ok, so I originally had the MAF hacked but I was unable to tune it that way so I went back to stock. As far as RPM, I based the 8K number on my logger reading as opposed to the tachometer. MAF overrun, I am surprised as well

I don't understand why you weren't able to tune. You have a SAFC or whatever, it shouldn't be an issue.

I don't know what's up with that rev limiter, very weird.

RT- 1.226
60ft- 2.322
1/8- 10.247
1/8- 68.89
1/4- 15.260
1/4- 90.93

Holy god, you're launching terribly slow. That's the main reason your trap speeds are low, definately.

Is your 1-2 shift fairly slow too?

When my car was trapping in the high 90s on pump gas (97-99), I was generally gaining somewhere around 19-21 mph from the eigth to the quarter. This is one of the best indications you have of the amount of power your car is making, because it is the part of the track that is least depenant on driver skill and traction.

On that pass, you gained 22 mph.

This is of course a rough estimation, but your car most definately has a good 5 mph or more trap speed left in it.

Your launch is not easy, it's just slow. Not a big deal at all, I remember when I started racing how weird it was to launch these cars, especially if you're used to something without AWD.

You should try to get your 60' times down to 2.00 or so. That's a pretty easy launch for me (when I bog, I usually end up in the high 1.9's), and I wouldn't worry about doing too much damage to the car in that range (as long as you don't wheelhop).

Your 1/8 mile time is very slow; I think it's due to the slow launch, but I also think that your 1-2 shift may be a bit on the slow side. With a 2.0 second 60' time and a 14.4 @ 95 pass, my eigth mile was 9.2 @ 75. I don't think that the 3 tenths difference in short times is the only cause of the whole second difference in eigth mile ET's.

So, try to launch the car harder, and shift faster.

It looks like your tuning is pretty good, although I would try to make a little more power with your setup. Definately pretty solid for now though.

 

[kpt4321]

A couple of quick questions to add to the rest... Is there any way to test the fuel pressure solenoid to see if it is working properly? Would a faulty FPS cause erratic behavior with the fuel/timing curves. Is the FPS something I should just bypass and if so, what would the overall effect be. Thanks for the help guys. I'm getting there, slowly, but I am getting there.

Just remove the damned thing, it's useless.

I haven't had one for years.

 

[92awddsm]

With a 14b car with stock injectors, I was able to run a best trap of 102 mph. That's a full weight 93, on pump gas, with only a clutch, full exhaust, and intake pipe.

You definately have a power production problem.

Second of all, I would advise against going to 7100 rpm at the track, it's just not worth it with stock cams and the 14b. Try shifting around 6500 to see what hapens.

I agree. You start to run out of air with the 14b by about 6000-6500 rpms. I shift my b16g at 6800 and well into 4th gear at the end of the 1/4 with trap speeds of 107mph.

 

[5150DSM]

Thank you very much for your time and knowledge. Sounds like its time to practice like crazy.

 

[kpt4321]

Thank you very much for your time and knowledge. Sounds like its time to practice like crazy.

You're welcome!

It's probably easier than you think. How are you launching now? Start out simply by revving higher and getting out of the clutch faster.

I was revving to over 5000 when I was launching without a stutterbox, IIRC.

 

[5150DSM]

I've been revving to 5-5.5K and then trying to thread the clutch out as I slam the accelerator to the floor. My main problem that I can see is that I almost always end up lifting the front tires off the ground. I am bascially in a 6-12" wheelie all the way through first, the only thing I can see is the hood. Honestly its a little unnerving. I was going to try and pulse rev on the launch and try and cut the clutch on the rpm upswing to slide out faster, I managed a 2.0 60ft with a broken tranny(rwd only) launching that way before and that was spinning all the way through first.
My previous drag experience has been in big-block rwd cars, in fact the last car I drove at the track before my talon was a '71 Elco and that was 10 years ago. The Elco was a 3speed sequential auto with a 12 bolt rear-end and positraction, which at 450+ hp was an interesting car to launch, it hooked hard and broke your neck out of the hole. Slam the shifter once, slam it twice, then the run is over. I could pull 1.8-2.0 all day and trapped 110-112mph running low 12's. Like I said though, that was a lifetime ago and in a completely different kind of animal.
Launching the Elco was brute force and sticky, sticky tires, launching my AWD is an art that I have not grasped at this point but I really think a stiffer suspension set-up would help me out. Bottom line, I should still be able to get out of the hole much faster than I am and any suggestions or techniques in that regard are more than appreciated. Thanks again for the help, between massive amounts of practice, and some DSMTuners guidance, I hope to have this car in the 12's by the end of the summer.
Aloha

 

[kpt4321]

Most DSM's with stock suspenion wil do that, I know my car does it too. There definately is a lot to be gained by getting better springs and struts, but on the other hand you can certainly get well under 1.8 seconds on the stock stuff.

I would be willing to bet that if you are not bogging, you are simply slipping the clutch too much. On a good launch, my car spins the tires pretty bad out of the hole and the back end steps out. More countersteer generally means a quicker sixty foot time (for the same conditons, etc).

Try this: On the first light, make sure the revs are where you want them, and bring the clutch up a little bit to get rid of all the "free play" at the bottom of its travel. On the second light, start to slip the clutch so that the car rolls forwards a tiny bit (you won't really move much, but you will take all the play out of the tranny and start the wheels in motion). On the third light, you can pretty much dump the clutch and hit the gas.

That's the best way I have heard the technique described to me, and that's basically what I do.

One thing to keep in mind is that reaction time does not effect ET. As such, feel free to spend plenty of time working on your launch, and don't go until you are ready.

I think the key is the light slip at the beginning to get the car rolling (again, not far. We're talking a foot here) and to build some boost. Then you dump the clutch and hit the gas, putting full power to the ground.

Let us know how it goes.