Engine Horsepower

[braganjackson11]

on a 2.25 petrol if i don't gas flow the head and have a machine shop build a short block with new pistons bored .030 over how much horse power gain could i expect? Is there a better cam available?

What differences are there between an unleaded head and a leaded one? Are these changes ones that can be made at a local machine shop?

[cdmbrennan]

Sorry don't know the diff between the leaded and unleaded heads- sure someone can chime in.

As far as boring out your pistons- you don't need a machine shop to build you a new block, just bore the pistons out yourself. Autozone "rents" the tool and it takes very little time to bore them yourself, get new piston rings, slap it together and bob's your auntie jean.

Turner Performance makes a high performance head for around $800- I believe they have a performance cam available as well. I believe the block is the same for a 2.25 and 2.5 as well, so with the proper modifications...

[Bogatyr]

braganjackson11,
I believe the only difference in the heads is the use of the hardened valve seats in the unleaded head. This is just because you don't have the added lubricity of the lead in the gasoline any more. Now, if you don't have any problems currently do you need an unleaded head? Prolly not unless you do a lot of high rpm driving...

Horsepower gain? Just keep in mind this is a glorified tractor engine. I think the most anyone could ever get out of one is on the order of 120 or so. I'm sure you would gain a few ponies by making the changes you mention, but would it amount to more than 10%? Not sure.

Some people, IIRC, have run the 2.5 liter cam in their 2.25 engines...one of the parts houses sells that cam as a replacement...BritPac? I don't recall...you might want to call around.

Bogatyr

[pickuprover]

For anything that you want to know about tuning a head have a look at this thread. Some very interesting suggestions and warnings.
http://www.landroveraddict.com/ubbth...ge=2#Post46415
The difference between the leaded/unleaded engine is the valve seats and the rings. They are as mentioned above heardened to withstand the lower lubrication and the higher cylinder temp.
As for boring out the engine. The extra horsepower is not really noticable. I would not do it if the engine is in need of boring. That being said, if your engine is tired (ie compression under 100 lbs) than a rebuild would definately give more power. I rebuilt my engine this summer and was amazed at the difference(however I will admit that the cylinder bores were so belled that I was surprised that I had any compression. )

[braganjackson11]

would a larger diameter exhaust and flowmaster muffler help any on the horspower?

[Muddy Oval]

You can't hotrod that engine- If you want horepower, buy a Jeep or do a complete engine swap to something entirely different. Stick a Rover V8 in it or something.

Autozone doesn't rent tools to bore an engine- they rent a hone... hones don't "bore" an engine, they smooth the cylinder before installing new rings.
You could spend $5K on that engine and even turbo it (it's been done), but you'd still have less horsepower than a Geo Tracker.

[Art Vigil]

Originally Posted by Muddy Oval

"You can't hotrod that engine..."

Well....sorta, but not really. Turner Engineering pulls a wee bit more out of the little 2.25 but I don't think you'd find anyone with a Turner rebuild who would ever accuse them of "hotrodding" it. It'll always be a 4 cyl engine.

I agree that anyone wanting more "performance" needs to replace it with something else. I think you'll be disappointed with the 2.25 if you expect huge gains after all that re-work.

-side note- I just drove Rita (my '72 S3 with a new Turner engine) for the first time a few days ago. I've owned her almost a year and finally she moves under her own power. I was thrilled!

Best of luck,
Art Vigil

[braganjackson11]

not looking to hotrod the engine, we're having to redo all of the exhaust and figured if we were gonna replace the exhaust we might as well make it as beneficial as possible and since flowmasters have been known to increase horsepower it seems the logical thing.

[pickuprover]

Any extra horse power that a flow master would give you would be neglible. As well I would worry that the flow master would not give enough back pressure. The other issue I see with going away from a stick exhaust is what happens the first time that you bend the pipes offroad. The main thing I like about the stock exhaust is that with minimal effort youcan replace one section as they are bolted together as apposed to sliding into one another. Having done lots of exhaust work on North American cars and needing either a torch or a sawzall to remove a section, I would never go back. I love the fact that if you use good stainless bolts in the flanges, after a couple of years you can still get the parts apart and replace which ever part is damaged. As well I would look into the stainless exhaust setup,but I have heard horrorstories about them not fitting and requiring major refittings.

[Muddy Oval]

Reduce the backpressure and you lose torque- lose torque on that little series engine and it won't move under it's own power. Turner eeks out a wee bit more power, but nothing to write home about. Even a turbocharged 2.25 only eeks out 100HP or so.
If you want torque, go with the diesel- then you gain a LOT- as well as fuel economy.