4.5 Stroker I love it but want more power....
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- Where's the "any" key?
- Posts: 22
- Joined: September 4th, 2008, 5:22 pm
- Stroker Displacement: 4.5
4.5 Stroker I love it but want more power....
This is my recipe it works great with no pinging on 93 octane gas, but I think i'm missing on some power benefits from a high performance cam, I feel the engine is stronger, plenty stronger than stock, but I'd like your experience on cams, I've been running my stroker for about 8 months and like it, but if i could have more power....
What cam would you recommend:
4.5 stroker
1993 4.0 block/ obd1
Stock pistons dished to 23 cc
no overbore
no block shaving
4.2 crankshaft and rods
Hi volume oil pump
Stock camshaft
victor reinz head gasket
Ford 24lb injectors
What cam would you recommend:
4.5 stroker
1993 4.0 block/ obd1
Stock pistons dished to 23 cc
no overbore
no block shaving
4.2 crankshaft and rods
Hi volume oil pump
Stock camshaft
victor reinz head gasket
Ford 24lb injectors
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- Donator
- Posts: 1245
- Joined: February 13th, 2008, 6:20 pm
- Stroker Displacement: 4.6
- Vehicle Year: 2003
- Vehicle Make: Jeep
- Vehicle Model: Wrangler
Re: 4.5 Stroker I love it but want more power....
daccarettfletez wrote:This is my recipe it works great with no pinging on 93 octane gas, but I think i'm missing on some power benefits from a high performance cam, I feel the engine is stronger, plenty stronger than stock, but I'd like your experience on cams, I've been running my stroker for about 8 months and like it, but if i could have more power....
What cam would you recommend:
4.5 stroker
1993 4.0 block/ obd1
Stock pistons dished to 23 cc
no overbore
no block shaving
4.2 crankshaft and rods
Hi volume oil pump
Stock camshaft
victor reinz head gasket
Ford 24lb injectors
With the pistons dished 23cc, and no block decking(high quench), I would think your compression ratio is pretty low. This could be causing a lack of power also. Running a bigger aftermarket cam might lower your compression ratio even lower because of a longer valve overlap and later intake valve closing. Have you ran your numbers on a compession ratio calculator?
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- Where's the "any" key?
- Posts: 22
- Joined: September 4th, 2008, 5:22 pm
- Stroker Displacement: 4.5
Re: 4.5 Stroker I love it but want more power....
Yes my dcr is almost identical to the stock 4.0
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- Where's the "any" key?
- Posts: 22
- Joined: September 4th, 2008, 5:22 pm
- Stroker Displacement: 4.5
Re: 4.5 Stroker I love it but want more power....
What if shave the cylinder head would that get my compression up?
- aaronkeiser
- Making Progress
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- Vehicle Year: 1991
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Re: 4.5 Stroker I love it but want more power....
Well if your compression ratio is very close to stock why not add a supercharger...? If you did it eat V8's for breakfast
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- Where's the "any" key?
- Posts: 22
- Joined: September 4th, 2008, 5:22 pm
- Stroker Displacement: 4.5
Re: 4.5 Stroker I love it but want more power....
As much as I'd love to...too much $$$$$$. The cam I can afford
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Re: 4.5 Stroker I love it but want more power....
daccarettfletez wrote:What if shave the cylinder head would that get my compression up?
Yes it would, but a lower quench will help with a higher compression ratio and still be able to run a lower octane gas. My stock 4.0 would ping on 87 octane. My stroker runs on 87 octane with .043 quench, zero deck(9.25:1 scr, 7.75:1 dcr).
- Biggrnjeep97
- I made it to triple digits!
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Re: 4.5 Stroker I love it but want more power....
If being cheap is what your after,ie: a cam, shaving you r head to raise comp. isnt a horrid idea, but it doesnt do anything beneficial for your quench numbers unless you install a thin(er) HG, like .043". If you shave your head w/o addressing some of your quench, you may open a can of worms(read: your knock could get very bad).
-Will
-Will
4.7 Stroker, AW4, Dana 60, 14Bolt, AtlasII 4.3, 104"Wb, 40" Nittos on Walker Evans
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- Learning to use the board
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- Vehicle Year: 1983
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Re: 4.5 Stroker I love it but want more power....
Most cams will increase you DCR. New cam, valve springs would help...
1983' Jeep CJ7 w/ 4.6L stroker, NSG370 6 speed trans, D300.
91' 4.0L engine, 0.030 over, 4.0L rods, 4.2L crank, KB944 pistons, Stock head w/ Mopar springs, Mopar cam, Mopar roller timing chain, Mopar oil pump, Hesco CPS relo kit, SS header
91' 4.0L engine, 0.030 over, 4.0L rods, 4.2L crank, KB944 pistons, Stock head w/ Mopar springs, Mopar cam, Mopar roller timing chain, Mopar oil pump, Hesco CPS relo kit, SS header
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- Cheromaniac
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Re: 4.5 Stroker I love it but want more power....
According to my calculations, the SCR of your engine is only 8.9:1 so that's going to blunt performance a bit but you should be able to run 87 octane fuel.daccarettfletez wrote:This is my recipe it works great with no pinging on 93 octane gas, but I think i'm missing on some power benefits from a high performance cam, I feel the engine is stronger, plenty stronger than stock, but I'd like your experience on cams, I've been running my stroker for about 8 months and like it, but if i could have more power....
What cam would you recommend?
I suggest you go for a Compcams 68-231-4 cam, upgrade to Mopar Performance 5249464 valve springs with matching retainers/locks, shave 0.030" from the block deck to increase the SCR to 9.5:1 (you'll end up with roughly zero deck clearance and a 0.043" quench), and add 0.030" thick shims under the rocker arm bridges to compensate for the increased lifter preload from the block shave.
While you're there, it wouldn't be a bad idea to replace the pushrods with Crower chromemoly hardened units and swap in a set of Yella Terra YT6627 shaft-mounted roller rockers to add stability to the valvetrain.
1992 XJ 4.6 I6 - 5MT - Stroker build-up, Stroker "recipes" Sold
1995 Mustang GT - 4AT - Modded Sold
2006 Mustang GT - 5MT - Modded Midlife Crisis Car
1995 Mustang GT - 4AT - Modded Sold
2006 Mustang GT - 5MT - Modded Midlife Crisis Car

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Re: 4.5 Stroker I love it but want more power....
Cheromaniac wrote:According to my calculations, the SCR of your engine is only 8.9:1 so that's going to blunt performance a bit but you should be able to run 87 octane fuel.daccarettfletez wrote:This is my recipe it works great with no pinging on 93 octane gas, but I think i'm missing on some power benefits from a high performance cam, I feel the engine is stronger, plenty stronger than stock, but I'd like your experience on cams, I've been running my stroker for about 8 months and like it, but if i could have more power....
What cam would you recommend?
I suggest you go for a Compcams 68-231-4 cam, upgrade to Mopar Performance 5249464 valve springs with matching retainers/locks, shave 0.030" from the block deck to increase the SCR to 9.5:1 (you'll end up with roughly zero deck clearance and a 0.043" quench), and add 0.030" thick shims under the rocker arm bridges to compensate for the increased lifter preload from the block shave.
While you're there, it wouldn't be a bad idea to replace the pushrods with Crower chromemoly hardened units and swap in a set of Yella Terra YT6627 shaft-mounted roller rockers to add stability to the valvetrain.
Don't forget to add the double roller timing chain to that equation. I found out the hard way

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Re: 4.5 Stroker I love it but want more power....
where is this thread? I would like to read it.Biggrnjeep97 wrote:read: your knock could get very bad
-Will
- SilverXJ
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Re: 4.5 Stroker I love it but want more power....
What he meant is that the can of worms he was referring to could be bad knock.Jak Flash wrote:where is this thread? I would like to read it.Biggrnjeep97 wrote:read: your knock could get very bad
-Will
2000 XJ. 4.6L stroker
00+ Viper Coil Swap | CPS Timing Increase Mod | Fabricated Airbox | Dash bezel, Arduino Multigauge & RD Conceal
Eat, breath, drink, sleep, Jeep, drink
00+ Viper Coil Swap | CPS Timing Increase Mod | Fabricated Airbox | Dash bezel, Arduino Multigauge & RD Conceal
Eat, breath, drink, sleep, Jeep, drink
- 1bolt
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Re: 4.5 Stroker I love it but want more power....
I'm going to go a completely different direction than anyone else...
What power do you want?
Do you want to leave riced up hondas 4 car lengths back at stop lights and chirp big off-road tires on dry pavement?
Do you want big peak HP numbers on a dyno sheet, Or want to pull on turbo'ed hondas doing 80mph on a lonely freeway, or zip around an off road dirt course at 4000-5000 RPM's for hours on end?
Do you want to "mile an hour" at the drag strip or "60 foot"?
You can't really do both under a small budget. If you can afford a cam, then you can improve power up high or down low (depending on what you already have), they both have there own set of unique design choices. Without making the engine larger or fundamentally more efficient (lower internal friction and higher breathing efficiency) you have to tune for one or the other. You can emphasize torque later in the RPM's or earlier in the RPM's (or somewhere in the middle where most mild cams will fall).
Horse power (AKA higher RPM torque)
bigger ports (larger cross sectional area), shorter intake runners, bigger throttle body, long tube headers with larger primaries, 2.25" or bigger exhaust, more cam "valve overlap" and duration and lift (less trapping efficiency to gain more CFM air flow at higher RPM's) low dynamic compression
Low/mid Torque
smaller ports, longer intake runners, bigger throttle body, long tube headers with smaller primaries, 2" or smaller exhaust, tight cam with little to no "overlap" period and moderate duration (air velocity and trapping efficiency more important than large CFM flow) high dynamic compression
Higher compression will benefit both, but you need to tear down, machine and re-gasket for that, same with better quench (allowing more timing advance and more compression before ping creeps in on the same fuel). Aftermarket fuel and spark control tuned on a dyno will probably improve both simply because the factory stuff has lots of built in "safety margin"and emissions oriented tuning choices, which a performance oriented tune will improve on. But that's expensive.
I would say you're not getting the most out of your combo, if you truly have near factory static compression somehow (as Cheromaniac figures) while having such bad quench, from the stock deck with 4.2 rods and 4.0 pistons. I'm terrible with numbers, but the last time I looked at that combo I seem to recall a 4.0 piston on a 4.2 rod and crank leaving the piston ENTIRELY too deep in the hole for effective quench... something like .090 or .100 quench distance... I'm not sure where that puts your static compression ratio but just off the top of my head I think it would have to be pretty bad... maybe I'm mis remembering. Dino did you take into account the pin hieght of his stock 4.0 pistons on 4.2 rods? I seem to recall this combo being an OKAY low budget choice with a block decking to get near factory quench, but without decking I recall it being pretty much unusable... I'm probably not remembering correctly.
What power do you want?
Do you want to leave riced up hondas 4 car lengths back at stop lights and chirp big off-road tires on dry pavement?
Do you want big peak HP numbers on a dyno sheet, Or want to pull on turbo'ed hondas doing 80mph on a lonely freeway, or zip around an off road dirt course at 4000-5000 RPM's for hours on end?
Do you want to "mile an hour" at the drag strip or "60 foot"?
You can't really do both under a small budget. If you can afford a cam, then you can improve power up high or down low (depending on what you already have), they both have there own set of unique design choices. Without making the engine larger or fundamentally more efficient (lower internal friction and higher breathing efficiency) you have to tune for one or the other. You can emphasize torque later in the RPM's or earlier in the RPM's (or somewhere in the middle where most mild cams will fall).
Horse power (AKA higher RPM torque)
bigger ports (larger cross sectional area), shorter intake runners, bigger throttle body, long tube headers with larger primaries, 2.25" or bigger exhaust, more cam "valve overlap" and duration and lift (less trapping efficiency to gain more CFM air flow at higher RPM's) low dynamic compression
Low/mid Torque
smaller ports, longer intake runners, bigger throttle body, long tube headers with smaller primaries, 2" or smaller exhaust, tight cam with little to no "overlap" period and moderate duration (air velocity and trapping efficiency more important than large CFM flow) high dynamic compression
Higher compression will benefit both, but you need to tear down, machine and re-gasket for that, same with better quench (allowing more timing advance and more compression before ping creeps in on the same fuel). Aftermarket fuel and spark control tuned on a dyno will probably improve both simply because the factory stuff has lots of built in "safety margin"and emissions oriented tuning choices, which a performance oriented tune will improve on. But that's expensive.
I would say you're not getting the most out of your combo, if you truly have near factory static compression somehow (as Cheromaniac figures) while having such bad quench, from the stock deck with 4.2 rods and 4.0 pistons. I'm terrible with numbers, but the last time I looked at that combo I seem to recall a 4.0 piston on a 4.2 rod and crank leaving the piston ENTIRELY too deep in the hole for effective quench... something like .090 or .100 quench distance... I'm not sure where that puts your static compression ratio but just off the top of my head I think it would have to be pretty bad... maybe I'm mis remembering. Dino did you take into account the pin hieght of his stock 4.0 pistons on 4.2 rods? I seem to recall this combo being an OKAY low budget choice with a block decking to get near factory quench, but without decking I recall it being pretty much unusable... I'm probably not remembering correctly.
--
Simon
Looking for a 232 crankshaft see my want ad: http://www.jeepstrokers.com/forum/viewt ... =17&t=1292
http://www.jeepstrokers.com 94 XJ Stroked lifted locked. 89 MJ restored Work truck, 88 YJ going on third build up and second Stroker.
Simon
Looking for a 232 crankshaft see my want ad: http://www.jeepstrokers.com/forum/viewt ... =17&t=1292
http://www.jeepstrokers.com 94 XJ Stroked lifted locked. 89 MJ restored Work truck, 88 YJ going on third build up and second Stroker.
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