Got my headers today & question 'bout crank scrappers

[b1gmoose]

I picked up a set of Ireland Engineering Shorty headers (not equal length :-( can't afford equal length in the ball park of 500$ used).

I also got the straight pipes and a near new o2 sensor. Picked it all up for 100$ even. Was gonna be 125$, but the seller cut me a last minute deal. Normally these are 350$ new so I'm happy even though they are used.

My next project (gonna take a few cases of beer to a friend) is to have them put on the car. Have to have the straight pipes cut so it can be welded infront of the catalytic converter. I would love to remove it, but it has to be there for the visual inspection for VT. Doesn't have to operate, and there are no emissions on an 89 vehicle. But I should keep it there anyways because it does get rid of nasty chemicals.

Hopefully I will see a moderate (.5mpg) increase in fuel economy. And even if I don't, the car will sound better and it wasn't much $$$ out of my pocket.

Any ideas on how a highflow-freeflow catalytic converter will boost fuel economy?

Also, has anybody run a crankscrapper in their car? I'm thinking about putting one in my car, just not sure when I'll have time time to install it. I have a special oil pan with a hole in it for the front axle to pass through for the front wheel portion of the AWD setup. So it will be labor intensive and I may pay a mechanic to do it for me, if I can estimate some gains from it.


~ryan

[SVOboy]

I've never heard of a crankscraper to be honest, haha. But I think your hopes for the headers make sense, though I have heard that headers will sacrafice low end torque for high end hp, which isn't the best in the mpg game. In any case, I don't think a high-flow cat is going to be worth it really. I know they cost like 300 bucks for a damn honda, so I dunno about for a bmw. Anyone, even the racers say it's pointless to drop your cat completely, meaning like .5 hp gain out of it, so a high-flow cat I don't think will make all the much difference really. Have you already done a cat back exhaust?

PS: see the ipod thing eh?

[b1gmoose]

I figure with header wrap from the block to the front of the cat will help keep the heat in, and create a stronger low pressure system to scavange hot air from the cylinder and suck cold air in even better. I may do some porting on the exhaust tonite when I install them. Every little bit helps with a SOHC inline 6 cyl engine.

Crankscrapers (sp) sit between the oilpan and the block. They come real close to the crank & rods. The goal is to get as close as you can without touching to scrape oil off of the rods & crank. This will reduce the roating mass (windage if I'm thinking correctly) of the oil, and thus the engine doesn't have to work as hard to spin.

They aren't expensive, just hard to install on my car.

A stock cat for my car runs about $450. A highflow cat I can find for about $250, and then it's a little fabrication to get it in.

Most BMW's if they are racing have highflow cat's or no cat. It is a pretty big restriction on these cars. GOtta remember the euro version of most BMW's in the 80's didn't have a cat or an o2 sensor, as a result they had anywhere from 10 - 30 more HP compared to the USA spec cars.

~ryan

[SVOboy]

Very interesting, being the environmentalist that I am, I'd say stick with the cat, but the crankscraper sounds very cool although awfully nitpicky. I'd go for it if it's cheap though, I love to do work on my car, just cheap stuff is even more fun. I've also heard port and polish will net you greater mpg from unrestricting things a bit.

[Matt Timion]

I have two conflicting opinions about cat converters.

Part of me says to do whatever you can do help the environment. After all, one of the reasons I want to get better MPGS is to help the future of the world.

THEN AGAIN, the other part of me says to just hollow out your cat so you pass visual inspection, or get a used cat from the junkyard and hollow it out.

Either way, your straight exhaust is going to be nice, and I'm really interested in knowing the marginal benefit of installing a straight exhaust and good header, although I'll probably never do it myself.

[b1gmoose]

I might bolt the headers & straightpipes up to the car and go for a 100 mile round trip that I do on a regular basis. I can tell you my avg mpg and my new mpg. It's all highway at 65mph, but lots of hills & rough pavement.

The catalytic converter does reduce emissions, but then again, my car gets 29.8 mpg compared to 21 stock. So even without a catalytic converter, I'm polluting less than my car in stock configuration.

I'll probably keep it though. I would harp on someone about hollowing theirs out, plus I don't like being stuck behind hickup trucks that have no cat, the smell is horrible, and that is all those nasty chemicals & gases. Plus, on a hot day, you can actually see more heat waves from a vehicle without a cat than with a cat. Kinda scary.

~ryan

[kickflipjr]

Removing the cat will probally give a tiny increase in mpg and HP. But it isn't worth the extra emmisions/ breaking the law.

My car came stock with a header (only 91 and 92 saturns have them). It gives the car a nice sound. But my RPMs haven't been high enough lately to hear it.

[SVOboy]

From what I understand mpg and emissions are not very closely related. The Honda Insight did not get some government grant thing because it's only SLEV even though it has the best mileage, while a new civic ex is ULEV or some crap. I dunno, emissions don't go with mpgs I am saying. I get better mileage than an escape hybrid by 33%, but I'm sure the escape hybrid has like a tenth of my emissions. Plus you'd have 100% more deadly poisonous stuff that is usually filtered, so yep, that's the bad smell.

[Flatland2D]

I've got a confession to make: I've got no cat. I even got my car inspected like this. Some places just don't care. Lucky I found one on the first try.

My car gets 6 mpg more than the Integra GSR the engine came from. My car is also about 365 lbs lighter. I have a suspicion the fuel economy might be even greater if I did my tests at 55 mph instead of 65 mph. My point is, is that I don't think the difference in weight could make up for all the increase. Some of the work that has been done to my car has probably been to the advantage of fuel economy. And the only thing my car has are "performance" upgrades.

Before anyone gets upset about my emissions, I will say one thing. One of the reported benefits of doing things like acetone and H2 is that emissions are suppose to drop (sometimes dramatically). I have heard people saying their car with no cat has far lower tested emissions than a car with a cat because they were on acetone or H2.