Stroke the 2.7?

**Jimsmag06** · 04-03-2007, 05:30 PM

Ok guys....what do you think about stroking the 2.7, or even .030 over cylinders.....Its been done in other engines, and not counting labor, would be drastically cheaper than the super or turbo chargers that, we may never see. Mazda is squeezing 270hp out of the 2.5 I4, we should be able to at least achieve 230hp or close.....What do you think?
-jim

**lafrad** · 04-03-2007, 05:46 PM

I think mazda gets that power with the assistance of a Direct Injected, high tech Supercharger, etc etc etc...

Something to consider is what you get out of beefing up the engine.

The small cylinder bore of the 2.7 will make a 0.030 overbore rather insignificant in the grand scheme of things. The bigger the starting bore, the more significant an overbore is (its a square relation... pi * r ^2)

Putting a stroker kit in will be rather unique (read: EXPENSIVE), as I believe no one has yet invested in creating forged cranks for the engine at any size. Since the engine is a smaller bore, stroking it gets you less displacement (but the percentage gains are good, compared to going overbore). Large Stroker kits generally REDUCE the "safe" redline of the engine, and the 2.7 as is WANTS to rev for power.

here is the suggestion then: If you are upside-down on the car and still want more power, Do what the Intrepid owners do, replace your 2.7L engine with a 3.5L engine. And now that the new Pacificas come with a 4.0L engine (bored/stroked version of the 3.5), you may even be able to drop one of those in the car... that would be a rather healthy torque increase, and, with the right injectors, your 2.7L computer should run the 3.5/4.0L car decently (maybe B&G could draw up a custom flash for you to get every last ounce of power...)

If you aren't upside-down, it really is more cost effective to find a used 3.5l car to start with. You don't loose any more mileage than a stroker kit would do to your 2.7, and to do get the increased torque... and you have no computer issues to worry about.

**LasVegasMagnum** · 04-03-2007, 10:05 PM

Wow...He broke out the algebra on you!!!

I think lafrad is right though. Trying to stroke that 2.7 won't have anywhere near the power results you're probably hoping to achieve. You're concerned about the cost of a turbo or supercharger? I hope you've got some smelling salts for when a speed shop tells you the price of a custom stroker kit!
I think the best thing you could do for that 2.7 is let it breathe a little easier with an exhaust and intake. I've always been a big fan of nitrous. Maybe a little 75 shot or something would be right up your alley?

**1sckmgnm** · 04-03-2007, 10:13 PM

Is there any intakes for the 2.7

**LasVegasMagnum** · 04-03-2007, 10:18 PM

I was thinking cold air intake. If you're in the mood to spend a little money, why not get the heads and intake ported a little?

**1sckmgnm** · 04-03-2007, 10:27 PM

I was actually wondering if getting the heads and intake ported a little would be worth the money.Would there be much gains from it?

**pigpen** · 04-04-2007, 12:54 AM

Do not buy the cheap Ebay intakes!! Find a good brand and if you can find the WR intake buy it!!

**Daedalus** · 04-04-2007, 01:19 AM

funny I can get a WR on ebay.

**Jimsmag06** · 04-04-2007, 01:23 AM

Lafrad, Thanks for the informative, in-depth reply. I have been staying away from the intakes and exhaust, because I have heard the computer "Negates" their purpose, and makes the performance and mileage worse, Though I find it hard to believe.
I, Like most of us out here dont like throwing money at mods just for the look or sound, and from what I have seen, the look and sound seem to be more important than performance. If things do get better money wise...I may just upgrade to the R/T.
Thanks again!

**PhatPhat** · 04-08-2007, 07:20 PM

I FOUND 4 ON EBAY, but no claims of what HP gains are....

**MagNite** · 04-08-2007, 08:19 PM

I would not use more than a 40 shot boost of nitrous. An Intrepid owner tried a 100 shot with a 2.7 and blew his motor. A CAI will give you about 6-8 more hp, but at high RPM. A good exhaust set up will give you about another 6 hp. You could try a turbo. A guy with a 3.2 Intrepid did that to his 3.2. raised his horsepower to around 300. Cost him like 5k+ and he had to pretty much custom make it. Your easiest bet for the most gain would be to get a good used 3.5 like everyone says.

**Detailsauto** · 04-08-2007, 09:13 PM

Originally Posted by pigpen

Do not buy the cheap Ebay intakes!! Find a good brand and if you can find the WR intake buy it!!

Ebay makes intakes??? I did not know Ebay was making stuff now. I thought people sold stuff on Ebay.

**Jimsmag06** · 04-08-2007, 09:18 PM

Originally Posted by lafrad

I think mazda gets that power with the assistance of a Direct Injected, high tech Supercharger, etc etc etc...

Something to consider is what you get out of beefing up the engine.

The small cylinder bore of the 2.7 will make a 0.030 overbore rather insignificant in the grand scheme of things. The bigger the starting bore, the more significant an overbore is (its a square relation... pi * r ^2)

Putting a stroker kit in will be rather unique (read: EXPENSIVE), as I believe no one has yet invested in creating forged cranks for the engine at any size. Since the engine is a smaller bore, stroking it gets you less displacement (but the percentage gains are good, compared to going overbore). Large Stroker kits generally REDUCE the "safe" redline of the engine, and the 2.7 as is WANTS to rev for power.

here is the suggestion then: If you are upside-down on the car and still want more power, Do what the Intrepid owners do, replace your 2.7L engine with a 3.5L engine. And now that the new Pacificas come with a 4.0L engine (bored/stroked version of the 3.5), you may even be able to drop one of those in the car... that would be a rather healthy torque increase, and, with the right injectors, your 2.7L computer should run the 3.5/4.0L car decently (maybe B&G could draw up a custom flash for you to get every last ounce of power...)

If you aren't upside-down, it really is more cost effective to find a used 3.5l car to start with. You don't loose any more mileage than a stroker kit would do to your 2.7, and to do get the increased torque... and you have no computer issues to worry about.

Yup, The Mazda is direct injected...
As far as turbo charging, I would probably use no more than 8psi of boost...I`m worried about the plastic intake plenum.
I dont think the 2.7 computer would run a 3.5, because the 3.5 has the 2nd intake valve servo, the 2.7 only has 1.

Wish They would come out with a 3.5 slant 6! That would be a really smooth, torquey engine!

**LasVegasMagnum** · 04-08-2007, 10:11 PM

Originally Posted by Detailsauto

Ebay makes intakes??? I did not know Ebay was making stuff now. I thought people sold stuff on Ebay.

You were thinking right. There's a vendor on ebay called Chrome Intakes. They sell a CAI for about $50. I got one while I wait on the Airhammer Sixgun. It made a difference in sound and my engine runs a bit smoother. Probably didn't make much impact in terms of HP.