Nice!
Jumbo's Silver FX - 2nd custom build
- Thread starter jumbosrule
- Start date
Buttonwillow Raceway this past Sunday. First track outing for the FX. Everything held up well... except for maybe the transmission. It doesn't seem normal - getting an inspection done. But I'm not sorry!
Most. Comfortable. Track. Day. Ever.
Average lap times at BWR were around 2:40, not pushing hard - maybe 7/10 effort. I wanted to drive home - which I did! Can you see the smiles?
Lapped with the dump valve wide open. GLorious engine sounds.
Most. Comfortable. Track. Day. Ever.
Average lap times at BWR were around 2:40, not pushing hard - maybe 7/10 effort. I wanted to drive home - which I did! Can you see the smiles?
Lapped with the dump valve wide open. GLorious engine sounds.
Major minor update!
Things have been good - I was cautious after the Buttonwillow track day; I had the drivetrain checked out at SpecialtyZ and there were no issues. What they did find was cracked flex pipes on the hot side. The accordian style flex pipes on both sides had cracked and caused exhaust leaks, so they were cut out and replaced with slip joints.
Since there was a six week wait to get into the shop, I decided to have a couple other things done as long as we were cutting and welding. Daily driving is done with the exhaust dump valve closed but even so, there was a rasp between 3500 and 4500 rpm. Not terrible, but not exactly refined either. We added in a high flow cat (there was none before) and a resonator. SO MUCH IMPROVED. Not quite stock, but not quite so much rice either. And as always, opening the dump valve allows me to be as obnoxious as I want.
Immediate throttle response improvement. Both turbo spool up and throttle modulation got tighter. This is much more likely from the flex pipe repair and not the exhaust fix.
Things have been good - I was cautious after the Buttonwillow track day; I had the drivetrain checked out at SpecialtyZ and there were no issues. What they did find was cracked flex pipes on the hot side. The accordian style flex pipes on both sides had cracked and caused exhaust leaks, so they were cut out and replaced with slip joints.
Since there was a six week wait to get into the shop, I decided to have a couple other things done as long as we were cutting and welding. Daily driving is done with the exhaust dump valve closed but even so, there was a rasp between 3500 and 4500 rpm. Not terrible, but not exactly refined either. We added in a high flow cat (there was none before) and a resonator. SO MUCH IMPROVED. Not quite stock, but not quite so much rice either. And as always, opening the dump valve allows me to be as obnoxious as I want.
Immediate throttle response improvement. Both turbo spool up and throttle modulation got tighter. This is much more likely from the flex pipe repair and not the exhaust fix.
T
twinkletoes
Guest
What's up jumbosrule. I'm a big fan. You're one of the main reasons I've signed on to this site. I appreciate what you've done w/both your rides. I noticed your 1/4 mile time, high 12's w/out loading up on the launch. Nice. Correct me if I'm wrong, but your on par w/rookie's time? He's got quite a bit more power, and surely quite a bit more loot under the hood. I don't think he wasn't going for all-out performance, nonetheless, that's impressive.
Would you be willing to share who you went to for the c.f. driveshaft?
TT- Thanks man! Appreciate the props, lol.
I've never taken the Silver FX to the strip. The time slips came from Big Red, using the same motor and turbo that is now in Silver. I had another run at 12.2 but don't have the slip so I never posted it. The launch could use the most help - software inhibits building boost while on the brake and both of these runs were done in automatic mode where the torque converter never fully locks up. In manual mode I think its possible to do a little better... but that's just a theory I have not been able to prove.
The quick answer is yes, Rookie's time was faster than mine but he had a manual trans swap done along with the Jim Wolf TT kit. The weak link in my build is the Auto Transmission because it starts to slip around 430whp while a Manual Trans can hold that power level and beyond. I'm on my third (built) transmission since the first turbo was installed in 2010.
The CF shaft came from the Driveshaft shop www.driveshaftshop.com. Custom application; I had to send them the OE shaft to have the CF made. They MIGHT have kept all the specs so if you are serious they may be able to produce another one without anything from you.
I've never taken the Silver FX to the strip. The time slips came from Big Red, using the same motor and turbo that is now in Silver. I had another run at 12.2 but don't have the slip so I never posted it. The launch could use the most help - software inhibits building boost while on the brake and both of these runs were done in automatic mode where the torque converter never fully locks up. In manual mode I think its possible to do a little better... but that's just a theory I have not been able to prove.
The quick answer is yes, Rookie's time was faster than mine but he had a manual trans swap done along with the Jim Wolf TT kit. The weak link in my build is the Auto Transmission because it starts to slip around 430whp while a Manual Trans can hold that power level and beyond. I'm on my third (built) transmission since the first turbo was installed in 2010.
The CF shaft came from the Driveshaft shop www.driveshaftshop.com. Custom application; I had to send them the OE shaft to have the CF made. They MIGHT have kept all the specs so if you are serious they may be able to produce another one without anything from you.
Well, I'm looking into some pretty major changes... mostly for fun.
I mentioned a few months ago that my flex pipe had cracked and needed to be replaced. Since that failure, it has happened twice more. The last time, I only had the car for two weeks before the pipe cracked and I lost the ability to build boost. Car was still driveable... just weak onset of boost. To me this is a good excuse to improve the system design.
SO this last failure caused a discussion with Specialty Z. We are not exactly sure where the stress is coming from but the solution is to create an ENTIRE new hot side. Currently the custom tubular headers are rearward facing with up-pipes that go through the wheel wells to the turbo merge collector. The Flex pipe sections were currently in the wheel wells.
The new and improved hot side is being planned so it's not nailed down yet but the highlights are:
-New tubular headers - FRONT FACING
-Two Tial wastegates on the up-pipes (instead of one single WG at the merge)
-Twin Scroll piping and turbo upgrade
-T4 flange & new mount
-Ceramic coating on all hot side pipes
These changes will shorten pipe runs, eliminate a couple joints, possibly reduce Primaries in size and be much more responsive. Progress to come!
I mentioned a few months ago that my flex pipe had cracked and needed to be replaced. Since that failure, it has happened twice more. The last time, I only had the car for two weeks before the pipe cracked and I lost the ability to build boost. Car was still driveable... just weak onset of boost. To me this is a good excuse to improve the system design.
SO this last failure caused a discussion with Specialty Z. We are not exactly sure where the stress is coming from but the solution is to create an ENTIRE new hot side. Currently the custom tubular headers are rearward facing with up-pipes that go through the wheel wells to the turbo merge collector. The Flex pipe sections were currently in the wheel wells.
The new and improved hot side is being planned so it's not nailed down yet but the highlights are:
-New tubular headers - FRONT FACING
-Two Tial wastegates on the up-pipes (instead of one single WG at the merge)
-Twin Scroll piping and turbo upgrade
-T4 flange & new mount
-Ceramic coating on all hot side pipes
These changes will shorten pipe runs, eliminate a couple joints, possibly reduce Primaries in size and be much more responsive. Progress to come!
Quickie update. Had about a month where I was waiting in line for my fabricator - but we are now being actively fabbed.
Some interesting things have been found - not good things, either.
First, the bellows in the flex pipe was cracked - we knew this. It's the reason the car went in the last two visits.
To compound this failure, the merge pipe failed as well. No wonder boost pressure dropped off!
The merge pipe has been repaired before AND we will be going to twin wastegates, so the collector is pretty much garbage. Fine with me since we are doing all new fab from the motor all the way to the turbo.
And then we found the CHRA leaking oil. This isn't necessarily a failure - there's nothing wrong with the turbo output or performance. But it will most likely continue to get worse so as long as everything else is out AND we are going to a twin-scroll GT series turbo, we might as well replace the CHRA.
Shot of the engine with the turbo removed; we will most likely come up with a new mount to try to limit the vibrations & loading going into the piping.
Some interesting things have been found - not good things, either.
First, the bellows in the flex pipe was cracked - we knew this. It's the reason the car went in the last two visits.
To compound this failure, the merge pipe failed as well. No wonder boost pressure dropped off!
The merge pipe has been repaired before AND we will be going to twin wastegates, so the collector is pretty much garbage. Fine with me since we are doing all new fab from the motor all the way to the turbo.
And then we found the CHRA leaking oil. This isn't necessarily a failure - there's nothing wrong with the turbo output or performance. But it will most likely continue to get worse so as long as everything else is out AND we are going to a twin-scroll GT series turbo, we might as well replace the CHRA.
Shot of the engine with the turbo removed; we will most likely come up with a new mount to try to limit the vibrations & loading going into the piping.
Sure there is a logic chain to that decision. Remember this car came out in 2003 and at that time, there was no option for a centrifugal charger. Stillen's roots blower was the only choice and it had such low boost capability it wasn't worth it to me.
Couple that with the fact that the centrifugal charger has maximum boost only at maximum RPM while the turbo was spooling up at 2400rpm; providing the hole shot and low end punch I think the big heavy FX needs MUCH more than a maximum top speed.
Then there was the fact that I already have a centrifugal charged Miata and I wanted a turbo because I had never owned a turbocharged car. I think the turbo (slightly undersized for the 3.5L motor) is the right choice for this street driven daily, just like I think the centrifugal is the right choice for my Miata track car.
skagen6675
Member
Nice set-up! I wish I was handy with an engine like you. I have an engine with 79k sitting in my garage waiting for some attention.
He's already answered but I've also had experience with both setups on the same car (not the FX but a VQ). They have very different power delivery profiles - peak power is similar but the powerbands are different at similar boost levels. Not hitting full boost until redline isn't a great feel on the street. Power is very linear but you feel like you have to push to high rpms all the time. Whereas with the turbo, you hit full boost around 2.5k or 3k depending on turbo. Vortech felt better from a stop since it would start boosting as soon as you got on the throttle. Turbo will get you much more power under the curve and the car will be much faster overall even though peak hp numbers don't look that different.
I actually swapped my Vortech for custom turbo due to reliability reasons. If the bracket for the blower is off even slightly, you'll shred belts. The Vortech is driven off the main belt which also drives the alternator so you'll have a limited amount of time to get the car home or to the shop. I lost several belts and had to get towed once - after that I got tired of dealing with it. If a turbo fails or a weld cracks, you won't boost but the car is still driveable.
SC kits are probably much more reliable now, mine was a POS Stillen kit (Maxima). But that was what kept me from getting a Vortech for my FX. I couldn't get over the complicated belt routing and memories of being stranded.
I actually swapped my Vortech for custom turbo due to reliability reasons. If the bracket for the blower is off even slightly, you'll shred belts. The Vortech is driven off the main belt which also drives the alternator so you'll have a limited amount of time to get the car home or to the shop. I lost several belts and had to get towed once - after that I got tired of dealing with it. If a turbo fails or a weld cracks, you won't boost but the car is still driveable.
SC kits are probably much more reliable now, mine was a POS Stillen kit (Maxima). But that was what kept me from getting a Vortech for my FX. I couldn't get over the complicated belt routing and memories of being stranded.
I know you wanted to go the custom route, but do you think getting a bolt-on like the JWT might have limited the turbo problems you've encountered? I only ask cause I want to eventually (VERY eventually) go turbo...Quickie update. Had about a month where I was waiting in line for my fabricator - but we are now being actively fabbed.
Some interesting things have been found - not good things, either.
First, the bellows in the flex pipe was cracked - we knew this. It's the reason the car went in the last two visits.
To compound this failure, the merge pipe failed as well. No wonder boost pressure dropped off!
View attachment 378243
The merge pipe has been repaired before AND we will be going to twin wastegates, so the collector is pretty much garbage. Fine with me since we are doing all new fab from the motor all the way to the turbo.
View attachment 378244
And then we found the CHRA leaking oil. This isn't necessarily a failure - there's nothing wrong with the turbo output or performance. But it will most likely continue to get worse so as long as everything else is out AND we are going to a twin-scroll GT series turbo, we might as well replace the CHRA.
Shot of the engine with the turbo removed; we will most likely come up with a new mount to try to limit the vibrations & loading going into the piping.
DatMan, ABSOLUTELY a bolt on kit would probably be less trouble in the long run. I had about two years of use in the current configuration before the major issues you see here started to surface. And remember this is my second turbo FX, so I have already been through major improvements with each build, taking advantage of what I learned from the last try.
Honestly things like this are expected with fully custom builds and that's actually what I like about them; the evolution. Knowing this is most likely a car I will keep forever (I say that about all my cars... which is why I have 3 concurrent projects, none of them running right now) I can continue to change and improve the system.
The build was never about big power because the we have always known the 5AT is maxed out around 425whp without modifications that start to change streetability. I've heard of higher power levels possible in the 350Z platform but that's not what the FX is all about.
This car demands balance if you are going to build it. I've seen the lofty power aspirations of other owners but the fact is this is a decently heavy SUV with a high center of gravity. Unless you plan on taking it to the drag strip, what are you going to do with 650whp? Trust me, it's fun at 400+ and you can get yourself into trouble very easily; that's how I lost the first turbo FX. I have a greater respect for the power and for the need to really think out the choices made in each supporting system so that the FX gets more capable without sacrificing the ride quality, street-ability and daily driver status.
In other news, I'm glad we decided to replace the CHRA. In fact, it became a necessity! Somehow I blew out the hot side wheel. Spark plug failure? Welding slag? Something hit the wheel. I'm surprised I didn't notice an event when that went down.
Wish I knew what it was but at this point we are fabricating an entire new hot side for the new twin-scroll turbo and replacing the plugs when we tune for the new setup.
Honestly things like this are expected with fully custom builds and that's actually what I like about them; the evolution. Knowing this is most likely a car I will keep forever (I say that about all my cars... which is why I have 3 concurrent projects, none of them running right now) I can continue to change and improve the system.
The build was never about big power because the we have always known the 5AT is maxed out around 425whp without modifications that start to change streetability. I've heard of higher power levels possible in the 350Z platform but that's not what the FX is all about.
This car demands balance if you are going to build it. I've seen the lofty power aspirations of other owners but the fact is this is a decently heavy SUV with a high center of gravity. Unless you plan on taking it to the drag strip, what are you going to do with 650whp? Trust me, it's fun at 400+ and you can get yourself into trouble very easily; that's how I lost the first turbo FX. I have a greater respect for the power and for the need to really think out the choices made in each supporting system so that the FX gets more capable without sacrificing the ride quality, street-ability and daily driver status.
In other news, I'm glad we decided to replace the CHRA. In fact, it became a necessity! Somehow I blew out the hot side wheel. Spark plug failure? Welding slag? Something hit the wheel. I'm surprised I didn't notice an event when that went down.
Wish I knew what it was but at this point we are fabricating an entire new hot side for the new twin-scroll turbo and replacing the plugs when we tune for the new setup.
Who else? Seb's the maaaaan.
I love following your journey with the FX and learning from what you've shared with us! I'm glad you don't mind being a guinea pig! 
In the end, I think I'd end up going with the JWT kit... It would probably be less expensive from the onset, and maintenance should be cheaper too... But that's still at least another 2 years away... I just want to know as much as possible before I dive in!
In the end, I think I'd end up going with the JWT kit... It would probably be less expensive from the onset, and maintenance should be cheaper too... But that's still at least another 2 years away... I just want to know as much as possible before I dive in!