Nick_08

I've got something in the works for the stock fuel tank 😈. @HipMF the late model e30 fuel tank uses a venturi type of jet pump to get fuel transferred over the saddle to the passenger side of the tank where the fuel pump is. The issue I had is that the venturi is too small thus restricting my fuel return and backing everything up (i.e my fuel pressure was not adjustable it was pegged at 70 psi due to this restriction). My fuel pump is massive like 525lph. @KaiserRolls this venturi pump is the reason a surge tank setup wouldn't work with the factory fuel system (unless you didn't plumb the return to the surge tank). You have to be able to transfer fuel over the saddle. Unless you have an early model tank. I found an aftermarket high flow venturi pump and I will be retrofitting a whole new hangar system to the stock fuel tank...hold my beer. Updates to come. In the meanwhile, check out my haggard (but it worked) fix to relieve the return fuel pressure.

I had planned on adding a surge tank once I run out of fuel pump. Since I've had to modify the return line because it doesn't flow enough and the factory tank having old rubber (not ethanol friendly). I think its a better and safer option to transition to a cell. I do agree @KaiserRolls, the factory tank is well positioned in a safe place and low center of gravity. Perhaps it may be worthwhile to pull the tank and modify it to fit dual pumps. There is still that venturi/return line that is responsible for transferring fuel from one side to the other. How do you get around that venturi?

Thanks bud! I forgot to mention, the flex sensor is placed on the fuel return line which is 6AN. The other line (feed) is 8AN. I have a question for the community. I have been really thinking about going to a fuel cell. What do you recommend and what should I look for? This is what the flex table looks like in holley, note that I stole this image from google images and the table is not set up properly. There is another table just like this that will subtract or add ignition time per the ethanol %. The possibilities are endless... As a former mega squirt/tunerstudio user, Holley is just way more user friendly.

Managed to get the flex sensor mounted under the car. I need to get two 6AN ptfe fittings to finish up the job (had the extra adapter fittings pictured laying around). I also decided to test my local premium 91 gasoline for ethanol content and contrary to what I've read on the internet, there is no ethanol (as advertised). The internet was saying even the premium-no ethanol still had some in it. Knowing the ethanol content is important because my current ve table is based on this fuel. The flex sensor should read this fuel as 0% and my will not add any fuel to compensate based on the flex multiplier table. Once the sensor begins reading ethanol %, the ECU will multiply my base ve table to administer the proper ratio. Hooray for being able to use any fuel available. The struggle of dealing with someone else wiring harness.....

I've considered just getting some fender flares but, I really want this car to look like a mostly factory e30 with some minor mods. So the only future option will be to go in...😈 For now and the foreseeable future, the TCS is my foot. I can't wait to see how these new tires (and the axles) hold up. Minor updates to come soon as the flex sensor mount will be arriving in the mail today.

Finally got the carriers, so the calipers are on. Still need to get some anti-rattle clips. The e46 caliper piston is about 5mm larger than the e30. On another good note i've got the flex sensor harness run through the firewall and wired in, I will be working on mounting and plumbing that in soon. It's going to be badass not ever worrying about the fuel you put in the car. With the flex sensor the ECU will automatically adjust the VE table and ignition table for ethanol %.

Starting the 5 lug conversion on the front end using the IRP kit, e46 bearings, and e46 325i brakes. Threw on some new sway bar end links while I was at it since those were crusty. I'm still waiting for the carriers to come in the mail. I will update with some comparison of the calipers, the piston diameter is quite close from e30 to e46. e30 (260mm) vs e46 rotor (300mm) e30 Hawk HPS (which are trash) vs e46 Textar, not a huge difference. The textar is taller and wider.

Here is the e30 vs e46 rear caliper. 32mm vs 40mm piston Go the tires mounted, took a look at the fender difference here, the passenger side has been rolled/pulled and the drivers side has not been rolled yet.

Wasn't sure if the extra $150 was worthwhile when I just drive on the streets? What have you had success with? I wan't impressed with the Hawk HPS.

205 vs 245

Just the regular pagid.

These are rebuilt e46 325i calipers. They fit with adapting brackets from SRS concepts. Completely bolt on, even the brake line. I will post some pictures/measurements of the factory e30 and e46 caliper side by side. The piston is much larger on the e46 unit. Part number: 34216758135 (left) & 34216758136 (right)

I'm converting the rear to 5 lug using z4 hubs, this adds minimal width (like 2mm per side) unlike the z3 and ti swap. This will allow me to remove the 20mm spacer/adapters needed to run the e38 style 5's and add a much larger tire. Going from a 205/45-16 to a 245/45-16. Anyway, I need more traction...so it starts. An added bonus is the e46 325i brakes a quite a bit larger. I do have to say, the B90 paid for itself again...worth the investment 10 or so years later. Edit* forgot to add, the e46 rotors are also vented...check it out.

I'm actually researching this right now. My wheel choice is e38 style 5 (16x8 et23). -e46 325 front brake rotors are 300 x 22mm -e46 330 front brake rotors are 325 x 25mm (as Mitch noted^) and there's a really good chance my wheels won't clear these. -e36 m3 front brake rotors are 315 x 28mm (as Mitch noted ^), I don't think these would fit either ( might be close). After much thought all day with the help from @KaiserRolls & @m42b32 I think I will end up going with the IRP 5 lug conversion kit and run the e46 325 calipers/rotors. These will be a decent upgrade from the e30 260 x 22mm rotor and in fact, the e46 325 setup will be 1/10th of the price of a massive BBK which is also only 300 x 22mm! In closing, I'm going to mark this thread as closed and thank you all for the information. Appreciate it... -Nick