ACR Reviews

[Max(SD)]

Is any one running the Powerplus ACR kit, it claims 43bhp over stock 2.25 engine. Is this for real?

Any idea of cost?

[TeriAnn]

Is any one running the Powerplus ACR kit, it claims 43bhp over stock 2.25 engine. Is this for real?

A 43 HP increase from a 70 HP engine????? That would give it the same HP as a fresh 300tdi only without the turbo.

Do they sell gold bricks & bridges too?

[Max(SD)]

thats why I ask, it seems unbelievable,

http://www.automotivecomp.com/landrover_perf.html

check out the link, scroll down to power plus camshaft

Power Plus © Camshaft + SU carb + Stage 2 Head + 43 BHP
over standard.

[rwollschlager]

I think what TeriAnn is trying to say is far better alternatives are out there for equivalent money but substantially more reliable.

[SafeAirOne]

I say "buy and install the stuff so we can all find out."

[graniterover]

Mark,

If you're not busy this weekend you can come over my house and put the power plus engine in my garage into my truck and we can test it. ;-)

Mark

[I Leak Oil]

With Mark's bad luck around engines recently are you sure that's what you want?

[LR Max]

I've got an ACR camshaft. It just has more rise on the lobes. That is it. I would look into a 2.5 camshaft, I've heard good things about that modification. Probably cheaper as well.

SU carbs are great for the road but you sacrifice low end some (AKA, off roading or towing or other truck-like applications).

For cylinder head, just get your current cylinder head shaved down to 9:1 compression. Get the valves lapped, port n' polish. Give you the same results without the $$$.

I've got a 9:1 shaved head, all that crap above and a rochester carb. My 109 goes down the road at 62~65 mph with no problem. Some loss of power on hills but generally I can take the trucks. Off road, no running out of steam in 1st gear. Sometimes in 2nd.

[TeriAnn]

thats why I ask, it seems unbelievable,

http://www.automotivecomp.com/landrover_perf.html

check out the link, scroll down to power plus camshaft

Power Plus © Camshaft + SU carb + Stage 2 Head + 43 BHP
over standard.

It kind of reminds me of the old J.C. Whitney catalogues. Start with a Chevy 327 engine then buy each speed add on and every fuel saver do dad including special spark plugs and that spinner do dad that sits below the carb and on paper you have a 600 HP 327 that gets 30-40 MPG.

Looking at the ACR page I can easily believe 6-15 HP increase by going to 9:1 compression flowing the ports & bigger valves ... but funny things about engines. A lot of time to feed one end of the RPM spectrum you have to starve the other end. Compression is always good and needed to get full potential out of a long duration cam.

But bigger valves and port passages plus smoothing out the passages really help with higher RPM flow but hurts low RPM flow and low RPM fuel mixing.

How far do you go for a street car vs a low RPM off road truck. My truck has a Ford 302 V8 in it. When I needed a valve job I decided to go to higher performance aluminum heads. Edelbrock advertised all sorts of power gains and showed stock vs their cylinder head dyno power curves. Everything looked good. Good power increase. But the graph started at 3000 RPM. I called their tech department to ask what happened below 3000 RPM. They said that their performance parts care not spec'ed below 3000 RPM. looking at the power curves if you extended the lines in the directions they were going, the Edelbrock heads would flow less than stock.

My V8 lives at lower RPM and only ventures North of 3000 RPM on a freeway on ramp. Off road it is often loafing in the 1500 - 2000 RPM area. Those high performance Edelrock heads would have been a big mistake. I looked at specs for just about every aluminum performance heads available for the engine and only found one version of one manufacturer's heads that flowed better than stock at low RPM. A company called Air Flow Research had a head that had smaller passages & valves than their all out performance heads that helped in the RPM range my truck's engine lives in.

Same with Cams. Your rob one part of the RPM range to add to the other. I avoided the speed cams that added power to the high end of the RPM range and went with a truck towing cam. The cam I went with was designed for low RPM power with little power increase above the RPM range my engine lives at. A performance cam would have meant less power at the lower RPM's my engine works at.

A few years back British Pacific wanted to add a performance cam to their product line up. They took a stock 2.5L cam to a Southern California custom cam shop and asked them what they could do to make it work better across the RPM range. After some profiling & testing the shop told BP that the stock 2.5L cam was very good for across the RPM range power. They could improve upon it a little but not enough to be really noticeable for the whole RPM range. What they could do is provide a street grind that would provide a strong boost at the higher RPM range but it would cost low end grunt. BP decided not to offer a custom high performance cam because they believed that Series owners wanted as much low RPM grunt as they could get.

I like SUs they are really good carbs on street cars. And a properly needled 2" SU has got to flow better than the stock carbs offered for Series trucks. Though I doubt if it flows better than a Rochester B series or the stock 2.5L Weber carb.

Stock Series exhaust systems are restrictive with a lot of back pressure. I've always been an advocate of swapping out the stock exhaust system for pipe that is one diameter larger plus a free flowing muffler.

And yes a K&N flows better than a stock filter, but it does not filter nearly as well. A good choice would be to run a K&N on the highway and switch to the stock system when you go off road.

I convoyed once with a 109 that had the ACR head, cam and SU carb. It left the other Series tucks in the dust on the highway and pretty much went with the V8 coilers on the highway.

So yes, from what I have seen the ACR stuff really makes a noticeable improvement at highway speeds. If you are building an engine for highway cruising and off road low RPM grunt is of secondary importance, ACR might well be the way to go for maximum acceleration on freeway on ramps.

Personally I would be very clear about the RPM range where power is important to the driving I do, then ask to look at dyno graphs of power vs RPM on the modifications.

ACR claims power increases but does not show power vs RPM graphs. You might well get that 43 HP increase at 4000 RPM but what happens at 2000 RPM? Go the ACR route and you will spend a lot of money and get a peppy road truck. I don't know what the curves look like at the RPMs you would likely be at on the trail though.

For a performance engine rebuild BP used to recommend boring the cylinders out to 0.40 over, a fresh 9:1 head, 2.5L cam, a fresh distributor with Pertonix conversion, a Rochester carb and making the exhaust more free flow. Their assumption is that Series folks wanted power increase clear along the RPM range.

Always good is increased cubic inches and compression. Add increased crank throw for increased low RPM torque.

If it were me wanting more power with largish budget and wanting to stay LR petrol, I go start with a fresh complete 2.5l engine with its longer crank throw and add the ACR Stage I 9:1 cylinder head. Then couple it to a larger diameter exhaust system with free flow muffler. I think it is about your best bet for an across the RPM range improvement and remain petrol.

If petrol was not an imperative, a 200 or 300 tdi would be my first choice. If I had money I'd look up a Brazil manufactured 2.8tdi that is based upon the 300tdi. That and a gearbox & axle upgrade

The ACR stuff looks really good for a street/highway Land Rover, but I would ask to look at power curves before parting with my money if I were building an off road truck.

[LR Max]

Stock Series exhaust systems are restrictive with a lot of back pressure. I've always been an advocate of swapping out the stock exhaust system for pipe that is one diameter larger plus a free flowing muffler.

And yes a K&N flows better than a stock filter, but it does not filter nearly as well. A good choice would be to run a K&N on the highway and switch to the stock system when you go off road.

Absolutely with the series exhaust. I had a custom 2" exhaust made for my 109. Huge difference through the entire range. I lost some engine compression braking, but fortunately I have wheel brakes to compensate for this.

The K&N-style filter is fine for off roading on the east coast. I had trouble with the K&N that BP sells (was too restrictive at highway speeds) so I got a cheapo whatever washable cone filter from the local auto parts store. No problems. However typically after a dusty weekend, it requires washing.

The Rochester carb has given me great power over the entire range. I recommend it. The Webber 1 barrel seems to work great at low end, but doesn't seem to provide as much at the top end.

[REDrum]

It kind of reminds me of the old J.C. Whitney catalogues. Start with a Chevy 327 engine then buy each speed add on and every fuel saver do dad including special spark plugs and that spinner do dad that sits below the carb and on paper you have a 600 HP 327 that gets 30-40 MPG.

LOL...Agreed!

[Jim-ME]

I understand the benefits a larger diameter exhaust system and a less restrictive muffler. What is out there that will work with an 88? I kept my stock Series exhaust when I had my diesel installed and it works. It is starting to rot out and I'd like to install a larger diameter system next time. Recommendations would be appreciated.
Jim

[TeriAnn]

I understand the benefits a larger diameter exhaust system and a less restrictive muffler. What is out there that will work with an 88? I kept my stock Series exhaust when I had my diesel installed and it works. It is starting to rot out and I'd like to install a larger diameter system next time. Recommendations would be appreciated.
Jim

I just went to my local muffler shop and asked for a complete new exhaust system one size larger in diameter and for a Flowmaster muffler. A couple chapters in my book later I drove out with what I asked for. They just bent the system up from straight tubing.

[PeterK]

I built up aN ex MOD sIII 109 a few years back with a 2.5 cam, Pierce 2 bbl manifold, 2 bbl Webber and 2" exhaust.
The power increase was nice, I can't guess how much but it drove an Ashcroft high ratio T-Case and 33 tires very well.
But it was expensive and the fuel consumption was horrid.

Here's a page of the build

http://www.cornerstone-studios.com/Jake/

I'm building a truck now with a 4.3 Chev V6 as I now feel it's an ideal engine for a Series truck one expects to drive at highway speed.

This discussion is timely, as the latest installment of the build video series is a rather dull ramble on about torque and hp.

http://www.youtube.com/watch?v=2LLSaYP0b0U&feature=g-upl&context=G2bc53bcAUAAAAAAAAAA

Cheers
Peter

[LaneRover]

Peter - thanks for making the videos, I always enjoy them and being a recovering Film and TV professional I know that just a simple video can add a lot of work to an already busy schedule.