HKS 264/264 fuel mileage

[turborebel]

How much does the fuel mileage suffer when the stock cams are changed to HKS 264s?

 

[MrBoxx]

Not sure about the 264's, but I switched from a stock 7bolt with stock cams to a built 6-bolt with FP2x's and I'm getting around 29mpg out of it. Before that, I got around 20mpg on the 7-bolt.

I know the engines and cams aren't exactly the same, so a good comparison can't be made, but I don't think fuel mileage will suffer enough for you to notice, assuming everything else is in good shape.

 

[1gDSM4g63]

I don't think cams make much of a difference. It all depends on your driving style.

 

[turborebel]

Thanks, that's good news. Mr. Boxx you got better fuel mileage with cams, thats really awesome. If I get better mileage with the 264s, I'll be a very, very happy camper. I have a set of 264/264s and a set of 264/272s, which ones would you put in?

 

[1gDSM4g63]

I have a set of 264/264s and a set of 264/272s, which ones would you put in?

That all depends of what turbo you're running to decide what cams will help your performance.

 

[turborebel]

I have the 16g now and when it wears out it will be replaced with the E3 16g. I would like more top end but not if it means less low end responce.

 

[1gDSM4g63]

Then the 264/272 would be the best since has a lower powerband which coincides with the 16g spools.

 

[Freerevving]

I really don't know any numbers with DSM gas mileage, as I can't say I've done much testing for that...
but on most cars, during normal driving, you get slightly worse gas mileage with larger cams. as a rough estimate 1 to 5 mpg on mild cams, 3 to 8 mpg on larger cams... It's more on V-8's..

264's won't hurt your gas mileage that much

 

[1gDSM4g63]

3 to 8 mpg is equivalent to 45 to 120 miles per tank and by all means if that were true I would have notice when I switch from 264/272 to 280s.

 

[crimsondragon]

Not sure about the 264's, but I switched from a stock 7bolt with stock cams to a built 6-bolt with FP2x's and I'm getting around 29mpg out of it. Before that, I got around 20mpg on the 7-bolt.

I know the engines and cams aren't exactly the same, so a good comparison can't be made, but I don't think fuel mileage will suffer enough for you to notice, assuming everything else is in good shape.

Are 6 bolts known to have better mileage than 7 bolts? It seems like the fact that the 6 bolt might be a newer engine with less miles contributes more to the lower fuel consumption rate.

 

[Freerevving]

3 to 8 mpg is equivalent to 45 to 120 miles per tank and by all means if that were true I would have notice when I switch from 264/272 to 280s.

Sorry I'm talking about city driving, and the change from stock... not from mild to large

FWIW highway mileage might only change by 1 or 2 mpg between stock and large

but you're going to lose some gas mileage with larger than stock cams

 

[turboglenn]

Are 6 bolts known to have better mileage than 7 bolts? It seems like the fact that the 6 bolt might be a newer engine with less miles contributes more to the lower fuel consumption rate.

6 bolts are older with lower compression ratio from the factory. This in turn generates less work from teh energy produced by the burning gas. So actually it would get less mileage in theory, and it is a LOT older than the 7 bolts as it had stopped being brought to america in 91 or so. The 6 bolts were manufactured in japan and the 7 bolts were manufactured in the united states for the most part. The real difference that bugs me is the bearing sizing on the 7 bolts, in an attempt to gain more consistant tolerances they used various bearing sizes in each motor by selecting them from a cross chart of crank journal size and the opeing in the block when the cap is on.


Anyway, enough about motor info... I have 264/272's and get pretty good mileage... ON a tank of 91 octane pump with about 4 gallons of e85 in it i got 28MPG highway and about 16-18 city depending on my habbits/foot... ON pure E85 i get about 14-15 in town and 18 on the highway.

Before on my 7 bolt i had broken over 30MPG on the highway and got about 19 in town. I think this was mainly due to higher compression ratio, slighly smaller cams than a 1g and better port design in the head. Even on stock 1g cams and 6bolt compression ratio i lost mileage over the 7 bolt

 

[1gDSM4g63]

Are 6 bolts known to have better mileage than 7 bolts? It seems like the fact that the 6 bolt might be a newer engine with less miles contributes more to the lower fuel consumption rate.

You got it backwards, 6-bolt are older than the 7-bolt engine and according to the specs of both engines stock the 7-bolt gets better gas mileage.

 

[webconnect]

Maybe he meant because there is a high percentage of people who rebuild their 6 bolts before putting them in?

 

[Freerevving]

Anyway, enough about motor info... I have 264/272's and get pretty good mileage... ON a tank of 91 octane pump with about 4 gallons of e85 in it i got 28MPG highway and about 16-18 city depending on my habbits/foot... ON pure E85 i get about 14-15 in town and 18 on the highway.

Just a guess, but I was probably getting maximum 16mpg city and 28 mpg highway with 272's in my 90 talon awd. and I'd have to drive it like a grandma for that

I've never owned a 2g, but higher compression ratios usually shine at the gas pump...
Not to mention 2g's have ports designed for torque, which also helps with gas mileage

 

[crimsondragon]

Maybe he meant because there is a high percentage of people who rebuild their 6 bolts before putting them in?

MrBoxx said a built 6 bolt with FP cams so I assume he must have rebuilt it and put in forged internals.

 

[TunaTalon]

More aggressive cam will move the power band and peak efficiency to a higher RPM and cams designed for more low end torque will be more efficient at lower RPMs.

All else being equal more aggressive cams will improve highway mileage and less aggressive cams will improve mileage in the city. Like about everything else about tuning these old cars we have to trade off something we care less about to get more of what is important.

The real trick is the "all else being equal" part. A higher compression ratio will improve mileage city and highway. Of course you have to give up higher boost levels to get the better mileage.

 

[jrohner]

I don't think my cruising mileage has changed much since I put in the BC 272 cams, but when I'm ripping around town my mileage seems worse. I did port the exhaust manifold and put on a huge FMIC at the same time as the cams though. I gained a LOT of power, so obviously it should use a lot more fuel when I'm hammering on it.

 

[kris_stewart10]

yea i am thinking about going to 272 272 cams

on my evo 3 cyclone engine

 

[havoc742]

Remember that cams change the duration and valve lift helping the engine run more efficiently. But when you get on it man does it suck fuel. The longer the Intake valve is open the more air and fuel enters the chamber.