Appointment is set with Vengeance on Monday afternoon for tuning. Will hopefully have some good news and numbers to report.

I've been driving around a bit on the base tune to make sure everything is functioning well. There is a little surge / bucking / stall at low RPMs which I figure is likely cam related. I've double checked all of my vacuum lines and stuff, but couldn't see any glaring issues. The car drives normally when it's moving. It seems to be making solid boost, but I didn't want to boost it too hard on a base tune.

The only random issue I've been seeing is the idle speed while the car is moving. While driving, when I push the clutch it, the RPMs sit around 2k. It doesn't come back down until I come to a complete stop, then it will drop back to around 900-1k (where I asked the idle to be raised due to the clutch / flywheel combo). I figure all of this can hopefully be tuned and get the car more driveable.

I'm also prepared for the possibility that I will have a 3hr drive there and something mechanical will need to be fixed before it can be tuned properly. Will keep you all posted.

 

Spoke too soon lol. Went to Vengeance on Monday and it looks like I have a fuel related issue that I need to sort out before we can tune it. Mike and crew spent several hours trying to troubleshoot the car. They went above and beyond, even after hours. It looks like the car is dumping fuel into the motor inappropriately. They tried multiple tunes, MAF / SD / etc…but still couldn’t correct the fuel issue. They did reach out to Josh at A&A and reviewed the logs. I ran a few tests that Josh recommended. A&A thinks it may be a fuel injector related problem. They’ve sent a new set of 80# injectors from FIC. I’ve ordered an HP tuners MPVI2+ Cable to datalog once it’s done. Overall really impressed with the support from both businesses. Will hopefully have some good news later and can share some numbers

 

A frustration for sure. Fuel bit me the first time too. I had driven down to NJ from CT only to learn that my fuel pump supplied pressure to 4k rom before nosing over for some reason. My first pump from racetronix was dead on arrival. Fully installed for all that headache and then no fuel. The replacement ran fine and I thought nothing of it while idling around keeping the car under 2k with a base tune. Sure as heck, three hours from home we learned it wasn't hitting full pressure. The third time was the trick. I switched to LPE for their version of the same modified walbro 255 and it has worked flawlessly from day one.

Best hopes for a speedy correction.

 

Thanks, that's wild that it took 3 pumps...and all of that labor!

So here is my issue. It looks like my STFT on both banks is way negative and this was the issue Vengeance was having last week. I recently bought HP Tuners and am getting a crash course in data logging and trouble shooting. You can see my STFTs at -34.4%



I've been retracing steps and trying to figure out what is causing the problem. So far I have swapped in another new set of 80# injectors, disconnected the power to the meth pump, and disconnected the power to the A&A external fuel pump. None of this has corrected the problem. Also the car apparently did the same thing in SD tune that Vengeance made, so it doesn't appear to be the MAF. Doubt it's a vacuum leak given how rich it's running and doesn't have positive STFTs.

My next thought is to temporarily remove the return system and FPR, cap the fuel rail and see if it has the same issues in a returnless setup.

My FPR sits at 58psi at idle, but not sure what it's doing during driving / partial load. A&A told me not to reference the FPR and to run static. Just wondering if all of this may be due to a bad "new" FPR? Vengeance thought it was weird that the psi never fluctuated during revving.



Whatever is going on seems to be all pre or post fuel rail, both banks seem equally affected. I thought it might be O2 sensor related. I mentioned before, but I was not able to run the rear O2 sensors up front because I couldn't find the appropriate harness. So I just got extenders to run the front O2 sensors in the front long tube position. I did this when adding the clutch and long tubes, but before the cam / SC kit / fuel / meth install. I was able to put 500+ easy miles on it with no issues so I know the car ran fine at that point. Plus the O2 sensors are both reading like 900+ mV, which I'm assuming is really rich. The AFR on my wideband holds around 13-14 at idle in this condition.

I've wondered if it could be a cam / valvetrain / timing issue as well, but not sure what parameters would be "off" and I definitely don't want to pull the cam cover again unless I have to do so. I verified the cam sprocket dots aligned but I guess it could have possibly jumped?

Still working with Vengeance remotely. Even though this issue is frustrating, I am learning a lot more about what it takes to safely tune these cars. It's been educational to say the least lol. Until I figure this issue out, they are not able to tune the car...but I really think it's going to be related to the return fuel system.

 

Small update. I temporarily disconnected the meth setup and capped the external fuel pump / FPR / return setup, so now it is running a basic stock C5 returnless setup with the new 80# injectors.

Before:


After:


I am still logging -34% STFTs. Sent some logs to Vengeance this week. Will hope to figure out a solution soon.

 

Are you sure that the BAP and secondary pump are working correctly? Have checked their function? On your BAP and External pump ground, did you grind off the paint on the frame so you get a good connection? It's hard to see in the picture.

Are the STFT all the time? Or only under load or WOT?

KT

 

Hi Pianoman90,
I'm pretty well known for building and tuning these cars as well as helping others with their builds. Ask around and I'm sure you'll get some decent feedback on me from those that I've helped. Anyways, I saw you have a clutch for sale and I PM'd you about it. Maybe I can help you get your car straightened out and we can do a deal on the clutch. Otherwise I'll happily just pay you for it.

Bret

 

Yeah I did check the external pump when I primed the pumps / lines, just jumped the hobbs switches. Everything seemed like it worked well, and I did use a dremel to remove some paint on the frame. I never connected the BAP since I went with the external fuel system.

I am negative STFT both banks at idle and partial throttle. I haven't really gone full WOT until we figure out what's going on, but the STFTs actually improve with moderate throttle and RPMs.

Also today formally removed the EVAP line from the driver's side intake. I capped the TB and left the firewall opening to vent. Just did another log and still -34 STFT both banks.

Random, but I'm starting to wonder if I might have purchased pushrods that are too long and maybe I've got a very small exhaust valve leak on each cylinder. I measured multiple times but they seemed way tight when I torqued them down. That would give negative STFTs and affect both banks. I might try to do a leakdown test soon and see if that's the issue. Sort of reaching here but I'm retracing my steps. The car was running / idling perfect before installing the mods, though I have no way of knowing if I had negative STFTs before starting.

I also didn't degree the cam during install. I did follow the install and had the cam gear / crank dots lined up. Just thinking of potential issues.

Hey Bret, thanks for the PM...just replied. Appreciate any thoughts you might have. I have to trust when Vengeance and A&A says there's a mechanical problem, there's a mechanical problem. If we can't get it sorted out, will definitely reach out for more detailed troubleshooting.

 

Sure, and I'm certainly not saying that I disagree with them at all. I'm just saying that there's a logical path to properly isolating the trouble and unless it's the simplest way, I'm not a fan of throwing parts at a problem until it goes away. It's just simpler for me to go back and forth over the phone VS the forum.

 

Def agree. The replacement injectors were courtesy of A&A at their request. Again shoutout to their customer support. So far I've only disconnected current parts in effort to isolate potential problems. I don't want to toss money away blindly. Got a weird work week this week but will give you a shout later to go over everything, that would be great

Also posted in the scan / tune forum, but here is my current tune and latest log if anyone wants to see it

 

Have you done something to the front O2 sensor wirings? Any kind of tin usage? Any extenders?

Is the AFR fine at open loop?

 

I deleted the rear O2 sensors with the longtubes and the car ran great. I wasn’t able to use the rear O2 sensors up front (what I heard was recommended) because the 04s have the square adapters front / rear and no one makes that adapter.

I did run an extender on both front O2 sensors. But the car was running / idling great in this configuration for around 500 miles while I was breaking in the clutch.

AFRs at idle are right around 12-13 on my wideband in open loop at first start up before going into closed loop. When Vengeance was road testing, they said they tried an open loop tune but noticed the fuel issues were still present.

 

Boy what a day! I ended up taking the car to a local LSX shop last week to sort the tune issue and got a call today saying they had street tuned the car and were about to put it on the dyno. They looked at multiple issues and think the problem may be an O2 sensor related issue. Ultimately they ended up doing a speed density tune in open loop to get the car running.

So the car ended up making 829 / 747 at 13 psi lol. I was expecting maybe like 650ish but wasn't even close. And this is only with 14 degrees timing. Honestly we didn't want to push it any more since I'm still on the stock bottom end.




The car drives so well right now. There is no surging, no idle hunting, no bucking or stalls. It's like a night and day change from the way it was running. Shout out to Calibrated Speed and Performance here outside of Birmingham. Austin there really did a great job and I'm very pleased.

Now I've got to figure out what to do moving forward lol. I think I'm going to have to either do a forged rotating assembly with the stock block or just go with a new forged motor / bigger displacement and pulley down. Then we can sort the fuel trim issue at that point. I would have liked a closed loop tune, but honestly I'm just happy to have the car running normally again so I can cruise around town.

 

That's a good day. Nice.

What's the final combo as it sits currently?

 

Thanks. So the final mod list...for now lol:

A&A V3 Ti with 3.6" pulley
80# Deka injectors
52mm Turbosmart BOV
NGK TR6 plugs
2 bar MAP sensor
IAT sensor spliced post MAF

A&A external dual fuel pump with return
Turbosmart FPR2000 - static
Alky meth injection

Tick stage 2 blower cam (227/243, .625"/.615', LSA 116+6)
Straub trunion kit
Tick hardened pushrods (7.375")
Tick .660" dual valve spring kit
Stock lifters
Stock heads
Stock bottom end

ATI stock sized balancer - pinned
ARP crank bolt
Katech C5R timing chain
C6 PS pulley
Melling 10295 high pressure oil pump (red spring / black o-ring)

Dewitts cut down radiator / cradle at stock height
SPAL fans
Stock thermostat

LG pro long tubes 1 7/8" with catless x
Borla stingers

ECS diff brace
Mantic twin disc ceramic with lightened steel flywheel
Hurst short shifter
Antivenom mod
New TOB
New stock slave cylinder
AEM wideband
Autometer boost gauge

Air pump delete / exhaust block off
EVAP delete from driver's intake manifold

Vibrant vacuum block to T fitting in brake booster
(2 lines to external fuel pump hobbs at 4 psi / 7 psi, 1 line to BOV, 1 to boost gauge, 1 to alky meth kit)

New fluids (diff / trans / oil / clutch / PS)
New intake manifold gaskets
New valve cover gaskets
New water pump gasket
New front timing cover gasket
New rear main seal

 

You love that lightweight flywheel yet? I'm addicted.

Your numbers are sick.

How did you set up the alky kit to run? Single, dual, nozzle size?

Comparo to what's sitting in my shop: same head unit and pulley, 10% od hub, similar ballpark cam, stroked, heads... I sure hope I like 800hp when I get to it.

What arr your street impressions?

 

I was able to drive it around a bit today but just started raining here. I'm running some really cheap 305s right now which limits the 1-3 gears, but definitely feels fast. I've never driven a centrifugal setup before this build. My old 04 cobra was roots style with a very flat torque curve, more on / off. The experience is unique with the linear power. It drives like stock until you put your foot into it and start building boost. I don't really want to fully wind it out on the stock block, but driving around town is a blast. And the lightened flywheel is great around town. It's nice to be able to slip the clutch like stock and not have the shuddering like a single disc. The idle is also set at 1000rpm and it has almost eliminated the clutch chatter.

Still noticed I'm dripping a little meth from the nozzle which stops about 1-2 minutes after parking. May need to see how to remedy this, I've already tightened it pretty hard.



Also planning to have a custom charge pipe made at some point to clean it up, now that it's SD and can eliminate the MAF along with some of the couplers / clamps.

Not sure on the nozzle size but I am running single nozzle, which ever size came with the A&A kit from Alky. I'm wondering if I should upgrade to the dual nozzle down the road at this power level?

You should be well above 800 then if you're running a 3.6 and 10% OD plus heads. Keep us posted!

 

Hello,
Been following this thread-Great results!
Question: How is the meth nozzle connected? Is it threaded into the pipe or a nut on the inside?

Thank you,
Steve

 

Its a pipe fitting. On the inside you typically have a washer with rubber gasket as the center to seal the pipe, and the actual nozzle itself screws down into the external fitting through the hole in the charge pipe. It ends up being a nice small part which can vibrate loose and catch the breeze down into your cylinder. (!) So it is worth loc-titing the heck out of the bugger. If I still decide to run it again on mine I'm going to toss a spot weld on the tip just to be certain. I'd rather have a fugly charge tube than nuke my block.

 

Thank you for the information!

Have a good Labor Day!
Steve