posted 03-20-2024 06:21 PM                  

One that I know works is using the crank out of the 4.0L SOHC engine used in the minivans. It increases the stroke from 81MM to 91MM sharing the same 96MM bore. You can also offset grind the stock crank and use a Honda small pin race rod. I like the 4.0L crank because the one I found was a twisted forging. Displacement increases, but the key is increased torque from the longer stroke. With the new pistons, there are some new ring sets available.

posted 03-20-2024 08:48 PM                  

I do not know how to make them more powerful. I do know that I have researched all this lately and it seems that the intake could (Emphasis on Could) possibly produce 3 to 4 HP. Headers look like they produce 4 to 6 HP. Exhaust and Free flow Muffler/Cats etc. ? 5 HP maybe ? So you have a 7% increase if you do them all. My question is, is that RWHP or Flywheel when people say "Headers add 5 HP". Then gears really wake the car up.

Do the higher temp Plugs do anything ?
Does Higher Octane fuel do anything ?

This I do know. Mufflers, Intake and Headers DO make a difference in the way they sound. And gears like you say, increase acceleration which helps you to get a wicked 2nd gear scratch. Which makes it just flat out fun.

I would think that all the 6 things above, gears, Intake, Headers, Exhaust, Good fuel and hotter plugs would be a way to drive more power. Like I said, no proof, but proof in the way the thing sounds and behaves on hard acceleration.

posted 03-20-2024 11:01 PM                  

I never seen the engine in I Scream, but heard stories or speculation

With the 4.3 & 5.0 strokers that were built it would be interesting to read just how they came about & what was done to control the programming for them

I read a lot on Facebook of people thinking they can do a few mods & make major improvements, would think what was done by many performance specialists back in the day that were unsuccessful & that today someone must have found a miracle performance shop

Improving Prowler Performance isn’t & easy or simple precess

Tony has the best solution

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Larry Mayes

posted 03-21-2024 05:28 AM                  

quote:

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Originally posted by RPL:
I see all of this talk about how to increase the performance of the 3.5L engine. I know what works and what doesn't. I once task Roush Performance to get me 300 HP. They couldn't by normal means. They could boost it by 50HP but that didn't deliver 300HP at the flywheel. One improvement suggested was increasing plenum volume which was the advice an owner in Grand Junction followed. Headers, cold air inlet and modifying the PCM didn't add 10HP. The gear set changes axle ratio and improves acceleration but doesn't increase power.

One that I know works is using the crank out of the 4.0L SOHC engine used in the minivans. It increases the stroke from 81MM to 91MM sharing the same 96MM bore. You can also offset grind the stock crank and use a Honda small pin race rod. I like the 4.0L crank because the one I found was a twisted forging. Displacement increases, but the key is increased torque from the longer stroke. With the new pistons, there are some new ring sets available.

I can tell you that the stroker engines were fun to drive. I'd like to hear some thoughts about this.

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posted 03-21-2024 07:49 AM                  

Iscream had a 3.8L stroker with a welded, off-set ground crank. Plus, Jerry had a unique throttle body set up and the car had a number of other unique features including Prowler Pro gears. My 3.8L engine ended up in John Davies car by mistake. You might ask him how the car ran. He had it out to the drag strip a number of times before I got the engine back.

The 3.8's and 4.2's were done with off-set ground cranks and different rod and piston combinations. The 5.0L that I was involved in had the cylinder liners bored out and the block sleeved along with on off-set ground 4.0L crank using small pin Honda race rods. It was roughly 4 1/8 x 4 1/8. The issue with the larger displacements is tuning the PCM. Back then it took an iBox to tune. Tony can do that today.

The supercharger was from Paxton. CJ drove the first one with the new Paxton headers on Larry Lord's Grand Canyon trip right off the floor from the SEMA Show. Her California Kid car has a Paxton supercharger. The heat shield that Larry Lord offers for the PCM was designed on her car.

Correct range spark plugs, not hotter plugs. Yes, premium fuel makes more power in Prowler. Why, because the engine monitors spark-knock and optimizes timing for each cylinder based on combustion. The Prowler and 300C were tested with premium fuel and rated at 253HP. The 3.5L Intrepid was tested with regular fuel and rated at 241HP. Does increasing octane beyond 93 increase power in a stock engine, the answer is no. Tuning is optimized for 91/93.

posted 03-21-2024 11:15 AM                  

I remember reading that the weakest link in the Prowler drivetrain, is the transaxle. Gearbox updates, as detailed in another recent thread should, maybe, be considered along with engine mods.

I'm no engine expert, but the modifying of an engine always seems like a more elegant solution for power rather than simply bolting on forced induction. Although, I can see the attraction.

With the stroker case, I assume shorter connecting rods are also required with the longer crank. Is any machining of the block face required to maintain the deck height? Compression ratio would also get a bump from longer stroke. Has anybody done any work on the cylinder heads of these engines? Like what size valves work well, where to remove material for improved gas flow? I'm guessing it's not a popular engine used in racing.

What about dropping in a Pentastar engine, has that been attempted? 305BHP from the 3.6L. Big job I imagine, new engine mounts likely plus fabricating an adapter for the transaxle. Again, all for 50bhp and not much boost in torque.