Questions on gearing, etc on a stroker

[gauss66]

Hi All - I am new to the forum, and have been thinking of a stroker for awhile. I am seriously considering a Golen 4.6, as I can do the drop in myself ( would be fun ! ).

I have a couple of questions:

1) Gearing: I have the 2003 auto with the very low overdrive. I have already regeared with 4.88s and seems to run just under 3000 rpm at 70 mph. I do some multiple hour drives on the highway, so would like it to drive in a sweet spot there. For those with strokers in the Golen performance range, what is a good cruise rpm. I have 32's, but could go to 33's ( which would look a lot better on my TJ ) and can regear after I drive it for a while.

2) I do like quiet - any recommends on what to do for headers back, but still allowing the engine to breathe ( I already have a KN filter - it was already on it when I purchased the vehicle in 2008. Just a little noisy on air intake )

3) Outside of 24 lb injectors and a TB, this would be all I plan ( unless I am missing anything ). The jeep is mostly logging trails, in town driving and some hiway when I need it to commute. It sits in the foothills on the Smokies when I spend time there. Purely a fun drive for me !

4) I have looked for some before and after dynos from a 4.0 to a 4.6, but have not seen any ( engine or rwhp ). If these are posted somewhere, can you let me know

5) I would like the most reliable performance for a stroker - seems the 260-270ish hp, 310-320 tq at the fly is at that point. If there is something more, that is not a finicky tune, let me know !

6) I fully realize I might break my d35 ( it does have strengthened axles and cover ), and will cross that when it happens. I do like my eaton trus !

[Cheromaniac]

I don't have any stock dyno numbers but I did a set of acceleration runs when my Jeep was stock and used them to calculate the rwhp/rwtq numbers. However I did run my Jeep on the dyno 6 years ago with the stroker and I haven't done any mods since.

Stock 4.0: 157rwhp, 201rwtq
Stroker 4.6: 202rwhp, 258rwtq



The stroker is aided by a bunch of breathing mods (Homebrew CAI with conical air filter, modified 65mm Mustang TB, 65-to-62mm tapered TB spacer, '01 XJ intake manifold (runners 3 & 4 lightly ported), ported head, Borla header, Flowmaster center muffler, Magnaflow rear muffler, 2.5" exhaust) with extra fuel added in the form of Ford Racing 24lb injectors and a MAP adjuster set at 5.3v. The PCM is stock.
I'm running 27.4" street tires and stock 3.07 axle gears with an AX15 manual tranny, so 70mph in 5th gear is at a relaxed 2100rpm but there's still plenty of passing power. The exhaust is a little louder than stock but sounds sporty under acceleration and is quiet at highway cruising speeds. CO & HC emissions are about half of what they were on my old strong-running 4.0.

[gauss66]

Thanks Cheromaniac ! I appreciate it.

I do believe I have seen a similar Dino chart on the golen site.

About 28% gain in both hp and torque and imagine my breathing choices would be comparable. The peak hp seems to align with the aceleration method ( was that a Gtech ? )

Are you spinning the tires in upper gears

Anything you would do differently ?

Thanks - Dan

[SilverXJ]

2) I do like quiet - any recommends on what to do for headers back, but still allowing the engine to breathe

Large case magnaflow muffler w/2.5" exhaust pipe. Larger the case, the quieter it will be and its still straight through design. I have a 24" (IIRC) on my 5.2L ZJ. Sounds good when getting on it, but not obnoxiously loud. Nice quiet cruising. Now, the small Borla I have on my XJ is a completely different case..lol.

3) Outside of 24 lb injectors and a TB, this would be all I plan ( unless I am missing anything ). The jeep is mostly logging trails, in town driving and some hiway when I need it to commute. It sits in the foothills on the Smokies when I spend time there. Purely a fun drive for me !

63mm TB, and build yourself an air box of some sort around that K&N so it draws in cool outside air. A tune of some sort won't hurt... at least a wideband O2 sensor/gauge so you can see what it is doing.

4) I have looked for some before and after dynos from a 4.0 to a 4.6, but have not seen any ( engine or rwhp ). If these are posted somewhere, can you let me know

I have before dyno, but i need to get my ass in gear and do the after one.

that is not a finicky tune, let me know !

A good tune is a part of the reliability equation.

6) I fully realize I might break my d35 ( it does have strengthened axles and cover ), and will cross that when it happens. I do like my eaton trus !

Easy on the pedal when you are going through obstacles. You could always upgrade when you break it.

65-to-62mm tapered TB spacer, '

What is the reasoning behind this? Keep up air velocity?

[Cheromaniac]

About 28% gain in both hp and torque and imagine my breathing choices would be comparable. The peak hp seems to align with the aceleration method ( was that a Gtech ? ) Yes

Are you spinning the tires in upper gears I can spin them in 1st gear and do donuts, 2nd gear if the road is wet, and 3rd gear if the road is greasy.

Anything you would do differently? I'd use the 4.0L rods and custom pistons to reduce the quench height and improve detonation resistance if I had to do it all again, but nothing else.

What is the reasoning behind this? Keep up air velocity? Yup, exactly.

[gauss66]

Thanks for the feedback on exhaust and tips on tuning. I appreciate it. If I am tearing an engine apart - I to would consider forged pistons, rods and hardened ARP nuts ...

I have talked to both Chad and Russ. Both great guys with different business models. Chad has locked into one type of stroker - his 4.6. Lots of trial and error, iterations to get where he is at now. He feels he is at a robust 270 bhp/320 tq that is good with the stock tune. Russ will vary his builds depending on the goals. For me - he feels he can get to the peak 300 rwhp/350 tq that is very drivable. Given distance - I would get components from him and find a local engine shop. His numbers are more seat of the pants from engines he has built. He is not a large production shop ( 3 stands ) and is comfortable at his size.

I also have emailed Flying Ryan - to get a sense of how he tunes. Having blown a few engines from extreme forced induction applications for pure bragging rights, and tuning via a fully programmable ECU, I would error on the side of sustainability now He seems like a good option - where you can get 10 tunes, and all the hardware needed down to the O2 sensor. For those that have used him - do you download and send files back and forth, or is the X3 wifi enabled that can send as is - as long as you tether to wifi ? This world wide tuning seems to be taking off ! I have a friend who tunes via megasquirt - but this approach seems more sane, vs building from scratch

I am still in search of what is a good cruise RPM for the highway. I am guessing mid to low 2000s. Neither Russ nor Chad had much of an opinion - guess they are more interesting acceleration

Thanks ! Dan

[jeepxj3]

Ryan is busy, expensive, emails tunes back and forth, you have to data log with wideband O2 sensor and send it to him. Back and forth. But he is good, worth the $ especially with a stroker.

Gearing-
Now- 4.88 32" 70mph=3000, 55=2350rpm, if change to 33" tires, rpm's will decrease by about 100rpm.
If go to 4.11 gears and 32" tires, 70mph=2525rpm and 55mph=1985rpm, 33" tires will decrease rpm again by about 100rpm.

With the added torque of the stroker, you don't need to rev it out like stock. 2000-2500rpm is a good cruise rpm range for 55-70mph.

Golen is a solid engine builder, Russ probably gets that 10% more power with finer attention to head porting, quench and cam selection. Unless you are racing, it is probably a toss up. It will really come down to lead time and $ total cost, and whether to have them do it- complete longbloock or use their parts and have it done locally by someone who doesn't really know the 4.0L very well compared to them. Their knowledge is easily worth $1000+ in the cost of the build.

Have you priced out all the different options?

[gauss66]

Thanks Jeepxj3

That is what I thought on rpms for the stroker ( mid to low 2000s ). Perhaps more the mid 2000's, as I would not want to match to just the ultra low overdrive, but also non highway driving. I'll drive for a bit before I regear - but I only want to regear once and hit the best compromise

The performance numbers I stated between Russ and Chad should not be taken as exact ( perhap's Chad's - but Russ's was from feedback he had from his customers ).

I have not gotten pricing yet from Russ - he is working on it. It would be a stroker kit ( he does not want to ship an engine and feels it can be assembled correctly locally ) and the cost to assemble ( believe it or not - there are guys who assemble jeep strokers in NC ! ).