Dat73z Posted February 3, 2022 Share Posted February 3, 2022 I mounted my FPR, Filter, and Fuel Rail on the firewall and ran stainless lines for the feed and return. I didn't think too much about it as some of my other vehicles which I've taken to HPDEs have this configuration both from the factory and what I've done in the past. After doing some further research it seems like this is banned from drag racing. I don't intend to drag race this vehicle but I do plan HPDEs and I'm curious if I should relocate these components and what the safety concerns are. Could those more knowledgeable let me know? I've attached some pictures of what I've done. Thank you Quote Link to comment Share on other sites More sharing options...
Dat73z Posted February 4, 2022 Author Share Posted February 4, 2022 After some further research this appears to be an unsafe configuration. So I'll need to chop the stainless hardlines at the firewall and run braided past the bellhousing to an alternate location. Surprised I never knew about this as all of my vehicles have had a similar configuration and I've seen more than a few cars like this at Buttonwillow and Laguna over the years at track days. Quote Link to comment Share on other sites More sharing options...
calZ Posted February 5, 2022 Share Posted February 5, 2022 If you wouldn't mind sharing your research, what's unsafe about it? Quote Link to comment Share on other sites More sharing options...
AydinZ71 Posted February 5, 2022 Share Posted February 5, 2022 The three outlets of your distribution block look a little close to where the valve cover & manifolds would be for an L-series. Is that what you mean? I couldn’t say they are “too close” though. In general you should avoid any penetrations in your firewall near where your fuel carrying components are, and most folks put their fuel instruments/filters/regulators on the passenger side of the car to avoid exposing them to engine heat. That way, if there is a fuel leak you may notice/smell it before it has a chance to ignite. You will always have at least one line going to your intake manifold/carbs, so that line just needs to avoid direct contact with engine and be a few inches above the manifold. Quote Link to comment Share on other sites More sharing options...
Dat73z Posted February 6, 2022 Author Share Posted February 6, 2022 On 2/5/2022 at 11:12 AM, calZ said: If you wouldn't mind sharing your research, what's unsafe about it? So I've asked around locally, on FB groups and a few forums and people are pretty divided on this. I think the most concise answers I received were from drag racers interpretations of NHRA rules which are basically: the firewall can and will deform in a crash, the lines by the bellhousing/clutch within a distance should be shielded or stainless braided in the event of clutch explosion, and generally if there is a fire on the firewall smoke and flames will enter the passenger compartment much quicker I think all of these concerns have merit but also based on responses I don't know how heavily enforced these rules are (I'm not a drag racer). Also as I was doing more research on early versus late model Zs it seems by the late 70s the 280z had moved the lines out of the tunnel and ran them by the framerail? This seems to make sense to me as you'd be in for a bad day if your driveline let go with all the plumbing in the tunnel. What threw me off is I've done numerous HPDEs over the years and haven't been questioned or seen anyone been questioned for fuel components on the firewall both OE and aftermarket. Even my Integra Type R has the filter bracketed to the firewall as factory with fuel lines running across. Doesn't mean it's safe but the response I got from drag racers on this one was OE cars have been rigorously crash tested so they get a pass (so people don't need to modify their OE cars with the configuration to pass tech). Either way to be honest not only for safety but also simplicity and flow I'm thinking you'd be better off staying out of the tunnel entirely, route the lines along the pass framerail and meet the engine at the front. Attach some skid plates or shielding for off track excursions. Here's some pictures of what I did in the original design, basically 20 or so bends per line with custom cnc machined brackets duplicating where the OE lines went. The tunnel can be a massive massive pita if you try and hug it close like I did. By moving to the framerail you'd only need a couple bends per line, much easier, safer, and better flow. These are in progress pics from my phone but I have the finals from the last iteration if you want anything for reference. Quote Link to comment Share on other sites More sharing options...
Dat73z Posted February 6, 2022 Author Share Posted February 6, 2022 23 hours ago, AydinZ71 said: The three outlets of your distribution block look a little close to where the valve cover & manifolds would be for an L-series. Is that what you mean? I couldn’t say they are “too close” though. In general you should avoid any penetrations in your firewall near where your fuel carrying components are, and most folks put their fuel instruments/filters/regulators on the passenger side of the car to avoid exposing them to engine heat. That way, if there is a fuel leak you may notice/smell it before it has a chance to ignite. You will always have at least one line going to your intake manifold/carbs, so that line just needs to avoid direct contact with engine and be a few inches above the manifold. Do you have any references to racing regs about this? I found a bunch for road racing/autocross about routing fuel in the cabin but haven't been able to find much on firewall mounting. A few people have brought up mounting a fire supression nozzle in that area but this is basically a 95% street car. Do you have any thoughts on that? Good points though. I think the fuel log is a few inches from the head. I don't think it's outside the realm of possibility that the head could move back/flatten the hood latch area and hit the fuel system in a crash as these cars will basically pancake the frontend with a 20-30mph frontal impact. Quote Link to comment Share on other sites More sharing options...
AydinZ71 Posted February 6, 2022 Share Posted February 6, 2022 @Dat73z I wouldn’t mix-and-match regulation from different race classes/leagues for a street application. Never seen/heard of a clutch exploding on a street car, but a scatter shield is required in many race classes. you are allowed to route fuel lines into your cabin in my race class, and the previous owner did just that. To say that is any safer than the lines being in the tunnel is crazy. If you have a fuel leak, you do not want it anywhere inside the cabin, and fittings do leak from time-to-time. I removed all his cabin lines and ran a new steel hard-line in the trans tunnel, similar to what you have. I would have transitioned the fuel line from the top of the tunnel to the lower passenger side (similar to OEM) near the bellhousing. That’s what I’m doing. The top of the tunnel is a high-heat area thanks to the nearby exhaust, and the fact that hot-air rises. The closer to the drivers side bellhousing, the hotter it gets. Fire suppression is required in my race class. Overkill for a street car (just get a hand extinguisher), and would require a lot of fabrication work. in general, hard-lines are more reliable and safer (assuming you pick the right wall thickness) than a flexible line. Braided stainless is very resilient, but it’s still capable of leaks and still has an elastomer inside. like I said before, the two most important things for the fuel system (street) is they should not be physically touching your engine anywhere, and they should ideally be as far from significant heat sources like your exhaust. the firewall comment I made earlier… see those heater hoses? In a fire, they will burn/melt. Your regulator is not far, so if that is where a fuel leak shows up, you can see a case where fire/fuel can get into your cabin at the heater hose bulkhead. We are talking worst-case, unlikely events so I’m still not convinced they are deal-breakers for a street car. Quote Link to comment Share on other sites More sharing options...
tube80z Posted February 10, 2022 Share Posted February 10, 2022 How is pulling a transmission with that setup? I know that may seem like a stupid comment but I also like to think about how hard it is to do basic maintenance items and changing the transmission clutch and pulling the motor are on my list. Cary Quote Link to comment Share on other sites More sharing options...
Dat73z Posted February 18, 2022 Author Share Posted February 18, 2022 @tube80z the L-series or 240sx adapted trans won't be an issue, as I kept the tube profile about the same as the stock 240z setup and running along the same hangers. You can see from my pics I even tucked the rear brake line up higher than where it would be stock (but still along the same path). You have plenty of clearance at the front by the block as well. Where you may run into issues is if you install a CD009 trans or one which requires completely removing the stock trans mounting area but I don't have a CD009 retrofitted car to compare. Quote Link to comment Share on other sites More sharing options...
Aggiestro Posted June 1, 2023 Share Posted June 1, 2023 How are you guys mounting the dual fuel lines to the frame rails…assuming your rubber isolators are shot like in my 280z? Butterflying P clamps in the old bracket fastener location seems like one fuel line will sit too low? Any suggestions? Thanks Quote Link to comment Share on other sites More sharing options...
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