Well, I had a pretty crappy night.

best pass in the evo was a 11.5 @ 125 with a 1.8 spinning the tires and letting off in first gear. I missed gears on the first 2 passes and spun tires on launch, after that, I had a fuel delivery problem that ended the night early.

I think the fuel pump is hurt. The first pass at 29psi/79% dutycycle had A/F ratio of 11.6 to 11.7..that was what I had tuned it to last time at track on racegas.

second pass, I turned the boost up to 30, duty cycle went up to 82 to 83%...but A/F ratio was in the 12.9 to 13.3 range. not good..knock like crazy..mph was like 125 or so.

third pass, I turn the fuel map up a lot, duty cycle goes up into 90's...but AF is exactly same 12.9 to 13.3. 125mph

I make one last pass, with dudty cycle at 100% most of the way...A/F is not into the 14's...ran 124mph I think

so I put 9 gallons pumpgas back in turn boost back to 24, load up the pumpgas map that was in the car on way to track. make a pass.

spun tires hard in first...12.1 @ 120 with a 1.9. I normally tune to 10.8 A/F on street/pumpgas...now all of a sudden im running 12.9 ti 13.5.

make one more pass, get decent launch 1.69 and run 11.9 @ 119...AF is in the 13s. not good.

I had to turn the boost down to below 20 on the way home to get the A/F ratio under 12.0 at WOT. at 20psi...it's pretty gehay slow.


so...ET's and launches sucked, and something isn't right with the car. Guess Ill swap in a new pump next week and check it out.

 

Wow... let me know what happened to the car. That is pretty bad man, I assume a walbro is powering it (You have been with DSMs long enough to know the opinion on the pump) so I wouldnt be surprised if it took a dump. Switch to a fuel cell I probably will be doing that along with other minor crap this winter. At 30 pounds you should at 128-132. You should be able to hit 123ish on pump.

 

What changes did you make to the car since the last time you ran? Weren't you going to a different housing?

 

Yes, I had the FP turbine housing on the car. As per the ems logs, it was making 490 to 500whp at 29-30 psi even with the F'd up A/F ratio, about 10 more than it made on the PTE turbine housing at 32psi with good tuning. It ran 125mph with rediculusly bad 60's and letting off in first gear.

Im pretty confident there is alot more mph in there than 125, As I said crappy night.

 

yeah, I was expecting to see 128-130mph pretty easy. Since the fp housing made about 20-30hp better on pumpgas/24psi, I honestly expected to see even bigger gains at 30psi and higher. The car was missfiring and poping alot in 3rd and 4th gear since the A/F was so lean. Knock pretty bad and ign timing being pulled There's mph right there in the bag.

It was a walbro 255. I can't remember if it was an HP or standard pump..whatever was on the shelf that day.

Im not going to a fuel cell, need to keep the trunk open for baby stroller. I think maybe Ill rewire the new pump. It's not so bad with the walmart pump, so long as you keep an eye on it. Had I just gone about making more runs without logging and checking it every run, I would have blown the motor.

Glad I don't have a reflash and no datalogger.

 

It nice to see some people actually posting all the news and not just " I got a new best time.."

I don't want to take your post too far o/t but what is the issue with the Walbro pump you guys are talking about? are they prone to failure?

 

they are when pushed to the absolute maximum. I was making about 500whp on it, and with the base pressure of ~40psi +30psi of boost...fuel pressure was in the 70's. The pump has to work harder to make more fuel pressure. The higher pressure puts more load on the bearings and parts in the pump too..wearing stuff out faster.

Walbro pumps aren't the most reliable pumps, in fact they are the cheapest and probobly lowest quality high output pumps you could find.

 

I like that part

 

yeah, if this fuel delivery problem would have happened to the typical "reflash-set it and forget it" evo8 owner, we would be arguing on a "did my tuner blow up my motor?" thread. It's getting more likely now that "10 second reflash-only" cars are showing up. Sooner or later, unfortuantly.

If not for the EMS's datalogger, logged wideband, and ability to quickly diagnose the issue, Im sure I would be sitting here today deciding to build a 2.0, 2.3, or 2.4 rather than deciding if I want to rewire the next walbro pump or not.

Im so glad nothing was hurt.

 

You, Trinababe, and evodave are driving 10 second cars, it's just getting the setup exactly right. I'll be there soon, I hope. That's awesome that it wasn't hurt. Are both housings .82a/r? What other fuel options are you considering?

 

i have a reflash... :-)

trinababe, this is for your signature...."excuses are liek a** holes, we all have them and they all stink"

 

yeah, your specificly the car I was refering too. What would you be able to do to diagnose or even know about a leanout condition if you ran out of fuel pump capacity, or the pump started to die a bit like mine did? Do you have a wideband guage in the car, and are you datalogging it with the obd2 software?

Im seriosly wondering here, as if a customer of mine wanted to build a car this fast that wasn't able to tune and diagnose problems themselves, I think I would have an issue just putting in a walbro and hoping for the best. Unfortuantly there isn't much available for "off the shelf" drop in fuel pump options.

 

Pretty sure both the PTE and FP turbine housings are in the .6 A/R range.

Im not considering any other fuel option yet than replacing the pump for a new one. It should be able to support the power Im making.

As for being 10 second capable, yes I think I can get a 10.9 out of mine with about 128-129mph if I can put a semi-decent launch together with making 3 clean gear changes. The tires and traction at the moment is a major hangup. When I get a second set of wheels and a set of dedicated drag tires, Ill be solidly in the tens.
My act clutch is also mostly worn out, Im thinking of moving to a twin disk with lighter disks to help with the shifting at 8500rpm.

 

I changed the fuel pump today, Out with one walbro GS342 255HP pump, and in with a new one. Simple direct swap.

A/F ratio is back to what I tuned for 10.8 to 11.3 under boost on pumpgas. no more leanout, and it's consistent again. Knock is gone. Basicly, the car runs just like it did before going to the track on friday. So the walbro 255HP did in fact start to kick the bucket.

So, I guess problem solved. Ill go back to the track on friday again and see what mph it can do.

 

Told ya the pump crapped out Im not sure but shouldnt the Supra pump fit into ours just like a DSM? I never had the Supra pump in any of mine but my buddy does and I am pretty sure it was a straight swap as with the Walbro. I will most likely switch to an Aeromotive pump or something similair when I swap to the cell but you wont have that option but you could still sump the stock tank and put an inline in but I think the Supra pump is your best bet if it will fit correctly.

I never even thought of the consequences down the road with all these flash happy campers. I never thought of what happens when thier cars break.. a 12 second car is pretty reliable and doesnt require many guages or logging but when you start knocking on the door of 10 seconds yes... My car worries the hell out of me I hit over 1900 degree EGTs regularly and run it on the edge of knock vs safe AFR wise. These people that don't even bother to read thier AFR's just make me giggle. Or the ones that log the stock O2 sensor... thats pretty accurate I could see some serious problems with blown crap down the road with no real way to see who is at fault... was it the tuner that tuned it too lean or the pump not handling it or the injectors failing or hose fell of the regulator etc...

Most of these reflashers really dont know how to diagnose the problems at all anyways. I was trying to help this kid that just got a DSMLink in his car. First thing that made me laugh was he couldnt get it started... (He didnt scale the injectors at all) but he figured he would just try to change the timing. Instead of using the DSMLink to modify the timing he actually loosed the cam angle sensor and started twisting it and kept trying to restart it. He finally loosed it to the point that it actually made no connection from inside of the cam. Anyways... make a long story short, somehow he got the car to actually knock while cruising. So he made some adjustments and figured he would do a pull and see if the knock was better at WOT. Needless to say, the car went poof. He was hoping it was the turbo so he pulled the pan and found metal shavings all over. He asked me if it was possible his turbo broke down and shot stuff into the oil pan.... now how the hell would parts of the turbo make it to the pan . Anyways, this same mentality will soon be hitting the Evo's and I think some rebuilders are going to make lots of money. We will find out.