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Old 02-16-2011, 09:48 PM   #1
JT99
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Question Quick Frankenmotor Question

I'm starting my frankenmotor build soon for my '99 OBS. I have a very low mileage '99 OBW engine that I am using for the bottom end. Putting 2.2 heads from either a 2000 OBS spare engine I have or am purchasing extra phase II heads if I can find a deal, as I'd prefer to leave a running spare engine intact. Going with Delta cams, though unsure of which grind to get. UEL headers and nothing-too-expensive catback. And a couple stickers that will add a good 20 hp. The car is my daily driver and I take short road trips regularly as well. I want more grunt off the line and not that worried about top end power gains.

Here's my question, for those who have experience with the 2.5/2.2 creature: Assuming you keep your foot conservative for normal driving, how much is MPG affected compared to your stock 2.2? (Share if you had 1000 or 1500 or 2000 grind, or stock cams, please.)
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Old 02-17-2011, 11:35 AM   #2
renob123
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Quote:
Originally Posted by JT99 View Post
I'm starting my frankenmotor build soon for my '99 OBS. I have a very low mileage '99 OBW engine that I am using for the bottom end. Putting 2.2 heads from either a 2000 OBS spare engine I have or am purchasing extra phase II heads if I can find a deal, as I'd prefer to leave a running spare engine intact. Going with Delta cams, though unsure of which grind to get. UEL headers and nothing-too-expensive catback. And a couple stickers that will add a good 20 hp. The car is my daily driver and I take short road trips regularly as well. I want more grunt off the line and not that worried about top end power gains.

Here's my question, for those who have experience with the 2.5/2.2 creature: Assuming you keep your foot conservative for normal driving, how much is MPG affected compared to your stock 2.2? (Share if you had 1000 or 1500 or 2000 grind, or stock cams, please.)
I can't help you with the mileage thing, since that's not a thing I care about with that car, plus my car is substantially lighter than yours.

For the unsure of which cams to get part, what I found from Delta when I got mine was that you should stick with the torque cams if you have not had head work. You can step up to the HP cams if you've had decent head work. This only applies to EJ22s. I have no idea what they recommend for anything else. In your case, since you want grunt off the line, get the torque cams. I did when I went to the Frankenmotor, and as I've said on the USMB, if you're spending any money on the performance of an EJ22, and you haven't already done cams, then you're retarded. That stands for you too

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Old 02-17-2011, 11:55 AM   #3
Matt Monson
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Torque cams...
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Old 02-17-2011, 12:48 PM   #4
JT99
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Thanks for the responses. Torque cams indeed do seem to fit the bill of what I want/need. I was able to dig some more in this site and others and find that the torque cam didn't affect MPG when driving lightfooted compared to factory MPG.

I've also seen a couple other people post that stock phase II EJ25 SOHC cams will serve a very similar performance in EJ22 heads that the Delta 1000 grinds on EJ22 cams do, so I may consider going that route as well. Money saved could be added to upgraded exhaust expenses.
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Old 02-17-2011, 01:00 PM   #5
renob123
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Originally Posted by JT99 View Post
Thanks for the responses. Torque cams indeed do seem to fit the bill of what I want/need. I was able to dig some more in this site and others and find that the torque cam didn't affect MPG when driving lightfooted compared to factory MPG.

I've also seen a couple other people post that stock phase II EJ25 SOHC cams will serve a very similar performance in EJ22 heads that the Delta 1000 grinds on EJ22 cams do, so I may consider going that route as well. Money saved could be added to upgraded exhaust expenses.
Cams from Delta are very inexpensive for your heads. Also, I'd bet that they can make better power than EJ25 cams that were designed with emissions in mind. I know that years ago, people went to the aftermarket for cams because aftermarket ones can increase the overlap, which isn't good for emissions, but is good for power. Considering one of your Senators is Rand Paul, I'm betting emissions testing isn't very common where you are.

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Old 02-17-2011, 02:39 PM   #6
Matt Monson
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That seems to get thrown around a lot without anything concrete to back it up. Here's my personal experience. Colorado's emissision standards are on par with CA with respect to tailpipe testing and are among the strictest in the nation. I had Cobb spicy cams on my Ej251 engine and passed multiple years in a row without issue. When they tightened the standard, I had to put the stock cats back on the car to get it to test clean, but continued to leave me built motor with cams and headwork in the car and pass just fine.

I have also passed several cars with Ej22 heads and Delta torque grinds in them. The cams pose no issue on emissions compliance and not only increase power, but when driven without red mist, fuel economy goes up, not down, by a couple mpg. It makes sense. They make the engine more efficient, so why shouldn't the mileage get better in regular everyday usage?
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Old 02-17-2011, 02:53 PM   #7
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Originally Posted by Matt Monson View Post
That seems to get thrown around a lot without anything concrete to back it up. Here's my personal experience. Colorado's emissision standards are on par with CA with respect to tailpipe testing and are among the strictest in the nation. I had Cobb spicy cams on my Ej251 engine and passed multiple years in a row without issue. When they tightened the standard, I had to put the stock cats back on the car to get it to test clean, but continued to leave me built motor with cams and headwork in the car and pass just fine.

I have also passed several cars with Ej22 heads and Delta torque grinds in them. The cams pose no issue on emissions compliance and not only increase power, but when driven without red mist, fuel economy goes up, not down, by a couple mpg. It makes sense. They make the engine more efficient, so why shouldn't the mileage get better in regular everyday usage?
I was referring to (but I realize now that I didn't mention it) non-Subaru applications. I first saw it mentioned on those Saturday-morning hillbilly shows on Spike (before it was Spike).

That's good info on passing smog with cams. I hadn't realized that.

I don't ever mean to doubt the master, but I'd like to point out that passing smog with Delta cams doesn't necessarily mean that the 2.5 cams were designed to maximize power. There could be some emission/MPG/cost considerations as well. I dunno. I didn't design them

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Old 02-17-2011, 03:53 PM   #8
grafton
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to your MPG question:

My build:
ej251+ej22e dual port heads
delta torque cams
mild port & polish
EL headers
Manifold spacers

around town my 2.2/2.5 gets 18-22 my old 2.2 got 20-23 on the interstate the 2.2/2.5 got 28-29.5 and my old 2.2 would get 29-31

almost the same economy but I've got a heavy foot
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Old 02-18-2011, 09:45 AM   #9
JT99
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Well, that makes me feel better about MPG. Threats of $4 a gallon gas might make a high compression build a bit foolish at the moment, but oh well. That's why you keep the stock engine in the corner of the garage I suppose...

I will think hard about just spending a couple hundred on the Delta 1000s, as I want to be sure I am doing what will pay off the best for the engine, as I'd rather not tear it apart again anytime soon after putting it together. I believe it was Storm who had posted about the stock EJ25 cams (when slid into the 2.2) being very similar to the Delta 1000 grinds, so I'm still gonna investigate that some more as an alternate route if the budget gets tight. I still have single port headers, catback, struts, and a timing belt kit to buy, so I'm trying to keep this as much a budget build as possible.

29-31 mpg? Was that a FWD Impreza? The best my OBS has gotten is 26. Are the OBS cars geared a little bit lower anyway? Course I drove a 95 Legacy LSi for almost 100k miles and it averaged 25-26 as well.
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Old 02-18-2011, 12:30 PM   #10
Matt Monson
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That's like asking what color blue is the sky? What's my point? My 2.5RS averaged 31mpg on the hwy when I drove is around 75mph. When I drove it around 80mph that number dropped to 27mpg. When someone says my "average hwy mpg is" it's wide open to interpretation.

What you do need to be aware of is the increas in displacement by adding the 2.5l block in there will drop your average mileage a bit from where you stand now, generally by somewhere in the neighborhood of 2-3mpg. But you've got other variables at play here too. My gas mileage got better with the addition of headers. When you change a bunch of things at once it's hard to measure the change. I changed things slowly over time and tracked the results, sometimes over years, to get my opinions on the matter. Individual results may vary.
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Old 02-18-2011, 05:59 PM   #11
grafton
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Quote:
Originally Posted by JT99 View Post
Well, that makes me feel better about MPG. Threats of $4 a gallon gas might make a high compression build a bit foolish at the moment, but oh well. That's why you keep the stock engine in the corner of the garage I suppose...

I will think hard about just spending a couple hundred on the Delta 1000s, as I want to be sure I am doing what will pay off the best for the engine, as I'd rather not tear it apart again anytime soon after putting it together. I believe it was Storm who had posted about the stock EJ25 cams (when slid into the 2.2) being very similar to the Delta 1000 grinds, so I'm still gonna investigate that some more as an alternate route if the budget gets tight. I still have single port headers, catback, struts, and a timing belt kit to buy, so I'm trying to keep this as much a budget build as possible.

29-31 mpg? Was that a FWD Impreza? The best my OBS has gotten is 26. Are the OBS cars geared a little bit lower anyway? Course I drove a 95 Legacy LSi for almost 100k miles and it averaged 25-26 as well.
I've got a 5 speed 2nd gen legacy, my wife's 4eat 99 OBS got 31 on the interstate once, cruse control @ 65 and no ac
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