Got grip, now found new problem

[mazur]

I'm sure of you remember my rant about how my car didn't grip and the brakes suck.

Well, I got myself some track pads and wrapped my weaves in 225 RA-1's and it feels awesome. Couldn't believe the improvement in longitudal grip...I couldn't even activate ABS.

Lateral grip was awesome as well. But has caused a new problem for me. Last session of the day and I'm having fun with an friend in an STi that was running really close times with me in Time Attack. I begine going around this long increasing radius turn and as I straighten out my car stop accelerating.

My first thought was fuel pump stopped working, but 3 long seconds later car accelerated again and felt normal. This happened 2 laps in a row so I gave up.



I had half tank of fuel and feel like that is a rediculous amount to have starvation problems with. Is there some type of fix for this? I was thinking adding an external fuel pump would help?

[iflytii]

The easy fix is to run a full tank of gas but that's pretty obvious. An external fuel pump won't help unless you change the pickup location. An external accumulator would likely fix your problem. I had the exact same problem so I went to a fuel cell with an internal surge tank. ATL makes a "well cell" that fits nicely in the spare tire well.

[nando]

I'm sure of you remember my rant about how my car didn't grip and the brakes suck.

Well, I got myself some track pads and wrapped my weaves in 225 RA-1's and it feels awesome. Couldn't believe the improvement in longitudal grip...I couldn't even activate ABS.

Lateral grip was awesome as well. But has caused a new problem for me. Last session of the day and I'm having fun with an friend in an STi that was running really close times with me in Time Attack. I begine going around this long increasing radius turn and as I straighten out my car stop accelerating.

My first thought was fuel pump stopped working, but 3 long seconds later car accelerated again and felt normal. This happened 2 laps in a row so I gave up.



I had half tank of fuel and feel like that is a rediculous amount to have starvation problems with. Is there some type of fix for this? I was thinking adding an external fuel pump would help?

now you understand why tires and pad compounds are much more important than bling items like BBKs!

does your car have the external and internal fuel pumps or just the signle internal pump? this is a semi common problem on E30s but I've never experienced it personally. I'm not sure why some people have had this problem - I generally have half a tank or less for autox and it's never been a problem (even down to the light once, but of course I filled up ASAP). I only have the in tank pump.

you could run a walbro 255lph inline pump in addition to the internal pump and it would probably help a lot - but your in tank pump could be going out as well. Also sometimes the relays are balky - maybe the cornering forces are affecting it as well. I don't think a fuel cell is really neccesary considering the amount of tracked E30s with stock fuel tanks and pumps..

[mazur]

now you understand why tires and pad compounds are much more important than bling items like BBKs!

Well, after getting used to new braking points, I'm now getting some fade within several laps, and since I'm not hitting ABS I'm guessing the brakes aren't up to par with the grip. So I'm still a believer in BBK's...or at least the "RX-7 Turbo BBK" upgrade...I've heard good things from a local E30 racer.

you could run a walbro 255lph inline pump in addition to the internal pump and it would probably help a lot - but your in tank pump could be going out as well. Also sometimes the relays are balky - maybe the cornering forces are affecting it as well. I don't think a fuel cell is really neccesary considering the amount of tracked E30s with stock fuel tanks and pumps..

I already have a new Walbro in-tank.

Just remembered hearing about the fuel accumulator from IE. Looks like I might pick this up.

http://store.nexternal.com/shared/StoreFront/default.asp?CS=ireland&StoreType=BtoC&Count1=701763331&Count2=618903756&CategoryID=3&Target=products.asp

[matt]

Any other indications that it is fuel starvation? Does your CEL come on? Does the motor knock coming into or out of this situation? AFRs?

[cheades]

Which track pads did you get? Do you still have the stock brake ducts, so far I haven't needed any more even going from 135 to 60, then short straight and 95 to 40.

I also only have the single fuel pump in the tank, never had an issue yet with it. Changed your fuel filter lately?

[etxxz]

i have that problem but only happens under 1/4 tank. i also believe that my transer pump is dead and whichever one is working is really whiny to the point that people think i have external pumps. i think the solution is new pumps or maybe our cars starve under really hard right turns.

[nando]

Which track pads did you get? Do you still have the stock brake ducts, so far I haven't needed any more even going from 135 to 60, then short straight and 95 to 40.

I also only have the single fuel pump in the tank, never had an issue yet with it. Changed your fuel filter lately?

you still using the pump from my parts car?

[mazur]

Any other indications that it is fuel starvation? Does your CEL come on? Does the motor knock coming into or out of this situation? AFRs?

No CEL, no knock, and don't have a wideband. It felt the same as when my connector went bad at the fuel pump.

The car just starts accelerating and when you let off the throttle it engine brakes faster. I didn't push the clutch in because that would shut my car off.

Which track pads did you get? Do you still have the stock brake ducts, so far I haven't needed any more even going from 135 to 60, then short straight and 95 to 40.

I had Cool Carbon race pads in front and HP+ in rear...have a set of cool carbons for rear but didn't have time to pick them up from a friend.

No ducting for me unfortunately. I have removed the front dust shields hoping that it will aid in cooling.

I also only have the single fuel pump in the tank, never had an issue yet with it. Changed your fuel filter lately?

Fuel filter was changed right when I purchased my car back in May.

[mazur]

i have that problem but only happens under 1/4 tank. i also believe that my transer pump is dead and whichever one is working is really whiny to the point that people think i have external pumps. i think the solution is new pumps or maybe our cars starve under really hard right turns.

On street tires I would only have the problem at about 1/4 tank, but it was in a fast left turn and wouldn't last for more than a second. This happened once yesterday at half tank as well:-?

[cheades]

Put your ducts back on, makes a way bigger difference than removing the backing plates.

[jlevie]

With respect to what might be a fuel starvation issue in a long right hand sweeper... If the fuel tank has a significant build up of sediment the inter-tank crossover tube may be plugged up. Since the sediment is mostly rust which is quite abrasive it will cause even a new pump to whine badly in short order. What you've mentioned makes me think that this is a possibility.

As to the brakes, you really need cooling ducts from the front spoiler to the front disks. And run the same pads front and rear. I have no experience with Cool Carbon Race pads, so I don't know how they'd compare with Hawk HT10's or PFC-01's. I can say the neither of those pads are likely to fade out with cooling ducts and proper threshold breaking. I run with ABS disabled because at best it is only going to result in about 85% of what my RA-1's can take and I've never had brake fade with either of those pads.

What brake fluid are you using?

If you aren't getting into ABS I'd say that you aren't threshold braking, which can lead to brake fade.

[mazur]

With respect to what might be a fuel starvation issue in a long right hand sweeper... If the fuel tank has a significant build up of sediment the inter-tank crossover tube may be plugged up. Since the sediment is mostly rust which is quite abrasive it will cause even a new pump to whine badly in short order. What you've mentioned makes me think that this is a possibility.

As to the brakes, you really need cooling ducts from the front spoiler to the front disks. And run the same pads front and rear. I have no experience with Cool Carbon Race pads, so I don't know how they'd compare with Hawk HT10's or PFC-01's. I can say the neither of those pads are likely to fade out with cooling ducts and proper threshold breaking. I run with ABS disabled because at best it is only going to result in about 85% of what my RA-1's can take and I've never had brake fade with either of those pads.

What brake fluid are you using?

If you aren't getting into ABS I'd say that you aren't threshold braking, which can lead to brake fade.

I'm going to see if I can figure up a ducting setup with some of that flexable tubing or whatnot that most brake duct kits use.

What do you mean by threshold braking? I've been braking hard and as late as possible.

I'm using the Blue stuff for fluid ;)


As for the fuel tank, I've looked in my tank before when changing my fuel pump and it looked as clean as a wistle in there. Plus I periodically use a fuel injection cleaner which I would assume would clean up the system fairly well.

[155///MPH]

With respect to what might be a fuel starvation issue in a long right hand sweeper... If the fuel tank has a significant build up of sediment the inter-tank crossover tube may be plugged up. Since the sediment is mostly rust which is quite abrasive it will cause even a new pump to whine badly in short order. What you've mentioned makes me think that this is a possibility.

As to the brakes, you really need cooling ducts from the front spoiler to the front disks. And run the same pads front and rear. I have no experience with Cool Carbon Race pads, so I don't know how they'd compare with Hawk HT10's or PFC-01's. I can say the neither of those pads are likely to fade out with cooling ducts and proper threshold breaking. I run with ABS disabled because at best it is only going to result in about 85% of what my RA-1's can take and I've never had brake fade with either of those pads.

What brake fluid are you using?

If you aren't getting into ABS I'd say that you aren't threshold braking, which can lead to brake fade.

QFT!

For some cheap great working ducts check out Factory 3 Performance. Some of the best bang for the buck out there.

Brake Duct Kits

Do yourself a favor and skip the BBK and get ducting and some real dedicated pads suchs as HT-10's or PFC's.

FWIW I use to have starvation issues starting at 3/4 of a tank. If you're seeing increased G's because of the new tires you will start to see the starvation symptoms earlier.

I use to run without ABS but got tired of flatspotting RA-1's in racing situations. Those aren't cheap. I ran my last race with the ABS engaged and it was GREAT. I do agree with Jlevie, its suspect if you aren't braking hard enough to engage the ABS. It comes on fairly early.

[bimmer freaks]

thoughts

I had a similar problem when I autox'd my car. The car felt like it literally shut off for a second or two and then it was on 100%. I thought it was fuel starvation, but it wasn't. It happened with a full tank and a 1/2 empty tank. It is some kind of electrical gremlin in the car.

Usually fuel starvation will give you kind of a stutter or coughing kinda feel, but my car seemed like it was completely shutting off then on. I changed the fuel pump relay and it stopped.....for a while. Then I changed the main relay and it stopped....for a longer while. Last time a took the car out was around 3 weeks ago for a practice event and it ran fine the whole time, but in the summer it seems to get this problem where after a High-G turn it will completely shut down and back up again. I put in used relays and was told to get new ones and it should clear up. Also, I don't know if you have ever felt how hot the main relay gets when racing, but it is screaming hot just from an autoX event. I typically shut the car down after a run and let the electronics cool down. Fire the car back up and we are good to go. I was considering putting a small computer fan in the fuse box to cool it down.

On another note, I would suggest either racing with a full tank or a close to empty tank. I know, you are going to say that you save weight with less gas, but a 1/2 full tank is actually detrimental because it acts like a tidal wave in your gas tank when you turn and messes with the handling of the car. Kinda picture a heavy weight sliding back and forth on your back seat. The inertia of the weight slapping back and forth in turns causes funny handling issues.....just my .02 cents. Good luck with the car. I love that thing!