Dollars per HP

[Plechtan]

I've been busy through the summer with the Bonneville truck and havent had much time to post. Things are calmed down now. I have been reading some of the posts on Turbos and looking on the internet at some of the supercharger kits. seems like 50-75 hp is all you get for $3-$4k dollars Doesn't look like a good "dollars per HP" deal.

I would think that most people are getting 30 hp or more from their stroker, probably with a $2,500 investment ( or less) . But you also end up with a fresh motor, which you would not if you just bolted somthing on.

I think that some of the HP we get from a stroker is really free or almost free. If you were going to rebuild a motor anyway, the only additional costs you have are for a 258 crank and maybe rods ( not needed with KB944s or custom pistons) So if you find an old 258 from a wrangler for a couple of hundred bucks, you are set. No wait a minute, you probably need some larger injectors. not big money but some cost is involved.

So maybe the first 30 HP cost about $10 per hp ($300) over just doing a straight rebuild. but what will the next 50hp cost? Head work? Borla Header? 99+ intake? Oversize throttle body? Cam? Unichip?

Be interisting to see the cost of a build and how much hp ( or torque) the engine produced. Anybody got any numbers they would like to share? What gives you the best bang for the buck?

[Cheromaniac]

The initial HP gains are always the cheapest until you reach the point of diminishing returns where you have to spend a lot of $$$ for a relatively small gain. My stroker cost me $1390 (plus another $240 for '01 XJ intake/PS pump/bracket) and though the HP gain over my old 4.0 with bolt-ons/ported head was modest, the torque gain was substantial especially at lower rpm (where the engine operates most often).
I think it would be fairer to talk in terms of $ per tenth of a second drop in 1/4 mile ET rather than $ per HP. I went from 15.23 @ 91.6 with my old 4.0 combo to 14.63 @ 94.4 with my current stroker combo.

[Plechtan]

I guess I am looking for the optimum build. Most people seem to spend between $2K-$3K on their builds and maybe put allot of time into porting the head. Is the money and time well spent? Does spending $500 on roller rockers really give you more performance or reliability? Would you be better off buying a borla header and an Alabama cylinder head and not reworking your old head?

Whats your Opinion?

[TurboTom]

I guess I am looking for the optimum build. Most people seem to spend between $2K-$3K on their builds and maybe put allot of time into porting the head. Is the money and time well spent? Does spending $500 on roller rockers really give you more performance or reliability? Would you be better off buying a borla header and an Alabama cylinder head and not reworking your old head?

Whats your Opinion?

I believe the rollers are a waste of money for anything running a stock EFI compatible cam.
I'm making 400 hp at 10 pounds of boost and running the stock rockers.
Best dollars spent will be on a MegaSquirt EFI and dyno tuning. IMHO
I do believe I would not have doubled the stock HP at 10 Lbs without the head work.
But I have to tell myself that after spending 2 weeks on the head
I run Tru-Value head bolts also. (socket head cap screws)
Turbos have always been the best bang or the buck, but you have to build the system yourself.
I would say I someone could copy my engine for $3500

[Cheromaniac]

I guess I am looking for the optimum build. Most people seem to spend between $2K-$3K on their builds and maybe put allot of time into porting the head. Is the money and time well spent? Does spending $500 on roller rockers really give you more performance or reliability? Would you be better off buying a borla header and an Alabama cylinder head and not reworking your old head?

Whats your Opinion?

Everyone's idea of an optimum build is different, and that's why we have various stroker recipes to suit peoples' needs. Different strokes for different folks you might say.
If you're staying naturally-aspirated, I think it's well worth the effort to port the head if you can do it yourself. It's worth 20hp at the crank on a stroker if it's done right. Roller rockers won't give you more performance but they will give you a valvetrain that's more stable at higher rpm. Kinda like having the cherry on the cake. You don't really need it but it's nice to have it.
Unless you have a potentially crack-prone '00-'01 head, it's better to keep what you've got and port it. Otherwise buy a junkyard 7120 or 0630 casting and only buy the Alabama 0331 head if you really need to have that casting.

[Plechtan]

Turbo Tom wrote:

Best dollars spent will be on a MegaSquirt EFI and dyno tuning.

Interisting comment, most people seem to just put bigger injectors in and do not do any tuning. They get a seat of the pants improvment, but really have no idea what a/f ratio they are running. They know they have a problem If they go way lean and get performance issues or damage the engine. If the engine is running rich, they probably have no idea.

Dyno tuning is expensive, Probably $600- $1,000 . For a radical engine you really have not choice but to have it done. For a simple stroker, if you increase the displaceent by 15% and increase the head airflow by 15% and increase the injector size by 15%, the stock ECU may work pretty well. However more radical changes would probably require a Unichip or replacement ECU ( like a megasquirt) to take full advantage of the modifications.

[SilverXJ]

Its not so much that the stock PCM can't accommodate the fuel flow, but that it is geared more toward emissions friendliness. With the correct sized injectors the stock PCM can provide a good AFR. As you said you can't really see what the AFR is without a wideband, so putting larger injectors on will help, but you won't be 100% there unless they are just sized perfectly. Even on a mild stroker one could find a few more horses just by going with an after market computer and having a performance oriented tune. Especially in the OBD II PCMs where it wants a 14.7 AFR until you really get on it. It wasn't so bad with OBD I though. I know that my 91 XJ with OBDI was a lot more responsive then my 2000 XJ. That is comparing them in both stock form and they both had the same trim levels and options, so their weight was roughly the same or not enough to make that much of a difference. Running 100% stock form my 2000 XJ was a complete dog compared to my 91.

If you went with an aftermarket PCM such as mega squirt a lot of money can be saved by doing the setup on your own and preliminary tune on the road. You could get pretty close to where is needs to be that way. Then take it to a dyno for the fine tuning.

[SilverXJ]

I run Tru-Value head bolts also. (socket head cap screws)

As in the hardware store?

[TurboTom]

I run Tru-Value head bolts also. (socket head cap screws)

As in the hardware store?

Yes sir!

[SilverXJ]

Yes sir!

Neat! Have any part numbers or sizes? What grade are you using?

[TurboTom]

Yes sir!

Neat! Have any part numbers or sizes? What grade are you using?

Just took stock head bolts and matched them. I had to cut 1/4" off 7 of them...only came in 1/2" incriments.
Also used one for the cam, worked perfect for the cam endplay. By the way, after all the dyno running and 3 shakedown passes looks like the bolt never touched the cover.
I looked at it after the piston broke.

[Plechtan]

I've done that already and the results are hardly mind-blowing, and not even close to Hesco's super-overinflated dyno numbers. Then again, that's exactly what i expected if you remember what i said in the EAP thread. Here are my "before and after" numbers:

Regards

Inna___

I have no idea what you are talking about, and i don't speak ( or read french)

[1bolt]

Spam bot, I just banned it, No wonder it looked on topic it just quoted Dino (Cheromaniac) from page 3 looked like a link to some French Identity theft protection service.

[Biggrnjeep97]

I run Tru-Value head bolts also. (socket head cap screws)

I was under the impression that the 4L factory headbolts were of a torque-to-yield nature, and with such a large cylinder head, proper torque procedures were required. You have no problem with 'em i assume? So what made you use those over the stockers? Price, availability, or was there a whole bunch of math im not getting?
-Will

[TurboTom]

I run Tru-Value head bolts also. (socket head cap screws)

I was under the impression that the 4L factory headbolts were of a torque-to-yield nature, and with such a large cylinder head, proper torque procedures were required. You have no problem with 'em i assume? So what made you use those over the stockers? Price, availability, or was there a whole bunch of math im not getting?
-Will

No real math. Needed bolts, went and bought them. When the piston failed I also reused the head gasket when I put it back together. Not really any cheaper, but I can reuse them without any worry. ARP studs are not designed for our appication either. They are just 1/2" studs that ARP believes are made of gold!!
You will find I don't do things like everyone else
In the big picture I'm not really making much horse power.