The SHO V8 is based on the 2.5 V6 block. It has the 3.25" bore/cylinders like the 2.5. Had it been based on the 3.0, they would have had a 4.0 V8.
I think the reason for 3.4 rather than 4.0 was politics. A Taurus with a V8 the size of one in a Lincoln or Jag? That would be direct competition and might take away from sales of the other two. Not likely, but it might have been a consideration at Ford. - James W. Gibat-Thoroski
Can we do what Ford was unwilling to do? The aluminum SHO V8 has cast in place iron liners with outside teeth that are not made for being pressed out. Cylinder liners are not serviceable and the track record of V-6 SHO's with healthy over-bores is not encouraging. The old liners would have to be destroyed to be removed, the block cleaned up, oversize liners pressed in and made to seal. It looks like a 4.0L engine could make 300+ HP for 30 days & $6000 and then go critical mass. Further information from the SHO Shop confirmed a no-go on the 4.0L V8.
Depends on how the 2.5 V6 compares to the 3.0 V6. The only difference between the two are the liners. The 3.0 V6 liners are much thinner. Are they exactly the same except for the liners? Then a bored out SHO V8 would act like a 3.0 V6 if the bores were the same. I plan to have the block sonic checked and have it x-rayed if possible. If I could find a Duratech 3.0 & 2.5 V6 block to have sonic checked too, then we could see if an SHO V8 could be bored to 3.50" to make the 4.0. - James W. Gibat-Thoroski
The even fire V-8 balance shaft made for the 3.4L could be wrong for the 4.0L.
I am going to try and remove this balance shaft. Going to take everything into a machine shop and they should be able to balance it so it is not required. It is more for NVH, but I am not concerned with smoothness...just power... - James W. Gibat-Thoroski
Update, Vadim is looking at this again, one of his buddies has been over boring SVT Contour engines. Vadim now thinks a 3.8L or 4.0L SHO V8 may be possible. It would however be less expensive and simpler to supercharge the V8 than undertake the redevelopment required to overbore the SHO V8.- Buford
Interestingly the engine balance shaft design is not as sensitive to stroke increases as it is to changes in rotating weight. (Ford told Vadim at the SHO Shop) A eight inch or quarter inch stroker V-8 SHO using a welded up crank and custom pistons seems much more feasible way to gain cubic inches than an over bore. For this to work the piston wrist pin would have to be moved up in the piston 4.5 mm as well to keep the same deck height. Will this interfere with the piston rings?
The pin would have to move down into the piston, not up. And yes, it would interfere with the pins. Buttons would have to be used to cover up the piston pin and the oil ring would be down into middle of the pin. The second ring would probably intersect it too. You might be able to go with a two ring system. Top ring and oil ring...this might sacrifice reliability though. The compression height is only 1.1811". That's SMALL! Going much below that is going to cause MORE rocking of the piston in the bore and more piston scuffing.
This also brings up the rods. You're going to have to get some expensive rods for that. The connecting rod journals are SMALL and you would have to go smaller if you offset the crank journals and grind them down...
I don't think stroking the motor is the answer, boring it is. - James W. Gibat-Thoroski
A 4.5 mm stroke increase to 85 mm would bump displacement from 3.4L to 3.64 or 7% more cubes. Would it be worth it? In theory it would not only make more power but also shift HP and torque down to lower rpm levels. The engine would be a touch less eager to rev but more power would be made down low where it is most welcome. A custom chip would be required. So far it looks like a bolt-on items like superchargers and NOS would give more bang for the buck and given the lack of basic parts (like head gasket sets) for the V-8 a lot more realistic.
Update, After inspecting a disassembled V8 SHO it looks even less encouraging. The wrist pin is very high in the piston and moving it higher would interfere with the piston rings.- Buford
The V-8 uses a unique design for their camshaft design. The shaft is tubular and lobes are each machined separately and pressed on. In the case of one camshaft, they perform more than one function, also driving the water pump making their design and construction complex.
In an OHC design, to get more lift and duration you have to cut to a smaller base circle and compensate with a taller shim stack. The factory lift is conservative but perhaps you can see the limits of the “smaller base circle, taller shim stack” an approach which risks self-destruction if taken too far.
I have seen a possible replacement for the water
pump on the SHO V8. Apparently a company is working on, and it might already be
out, an electric water pump. Yes, yes...they make these already for chevys and
Fords, but...they are race items and not really designed to work on the street
for extended periods. Apparently this company is coming out with a street
version of an electric pump. This would allow the SHO V8 to get rid of that
mechanical pump and reduce the load on the cam. This would also reduce drag on
the motor and increase power. More when I hear or find more about it. - James W.
Assuming we could get blank cams (we can’t) or machine our own (very complex $$$ design) the valve springs would have to accommodate the increased lift without binding or going solid. Who makes reliable hi-lift V-8 SHO valve springs? Good question.
That will be easier to answer when I get the valve
springs off the head and measure them. You could easily get a set custom done at
Comp Cams or Crane. Just give them the dimensions and they will do it...wouldn't
cost much more than a standard set of springs. If lucky...they might match up to
some other type of springs and you could by replacement springs for a Ford 5.0
and have them installed...it is a possibility any ways. - James W.
V-8 SHO valve shims are not the same as V-6 shims and unlike the V-6 no shim adjustment is required at 60,000 miles. Hence the natural opportunity to access the cams is delayed until 100,000 miles.
The only source for cam blanks is the junk yard. Development, each selection of cam profile for testing requires the death of a 96+ SHO. Once a prototype exists the problems remain of acquiring cams for the customer or cutting the customers. DOHC V-8 have four camshafts, a weld up and re-cut job could involve $1000 in just machine work, plus the cost of labor, and parts. Budget $2500-$3000 for the project, not including development costs which must be passed on?
You can get them at Ford. I have a price list
somewhere. For the entire set of cams, it's around $600-$700. Order up a couple
intake cams, grind and weld on them and try them till you get some good flow
figures and try the good ones. Then duplicate them. It won't be cheap...but
then, you have 4 cams. A set of cams for a 4.6 Cobra motor is $1200 or more, and
they are just reground factory cams. - James W. Gibat-Thoroski
Even if the technical problems can be overcome, the cost of development is too high given the lack of natural demand.
Yep...this motor isn't a "do-it-yourself" type motor. It's not something like a 5.0 that you can just tear into and replace parts cheaply and easily. - James W. Gibat-Thoroski
Update, based on simulation studies the factory cam is very radical for a street motor. It is already what old timers call 3/4 race cam. A more radical camshaft would require headers, a lighter car, deeper final drive ratio and a manual transmission so the engine would always stay on the pipe. Crane Cams confirmed that recent Ford performance cams leave little (as in none) room for improvement. Ford has them developed to the nth degree.
Extrude Hone Exhaust Manifold
It was tried and the ample exhaust manifold made less HP when hogged out. The cavernous castings indicate either more displacement or rpm may have been planned at one time.
Extrude Hone Intake Manifold
How about an extrude hone on the V8? Doug Lewis’s (FPS Auto) comments: “An extruded honed intake system for the V-8 SHO made no HP but cost a lot of $$$.” Because the Contour sports a extrude honed intake it was worth a try.
If you have any insights or ideas, based on these or others that will help motivate 96+ SHO please feel free to drop a note to me at firstname.lastname@example.org .
Special Thanks to Vadim at the SHO Shop, Doug Lewis at FPS Auto and many others (especially 89-95 SHO owners on the SHO-times mailing list) for helping us sort out the feasibility of our HP plots and schemes. They have been most generous with their time and expertise.
From 1996-97 when the car was new and we had lots of hope and innocence.
update thanks to Big Dog.
I don't need a show of hands..... But is anyone surprised Tim started this thread?
Timothy J. Wright
I talked to Doug Lewis last night about my third generation SHO. A chip should be out in about five months, worth 20-30 HP, I'll replace the sub-frame bushings and sway-bar bushings at the same time. Sometime soon I'll rent rib retractors do the cone-otomy. How much is that worth performance wise?
I'm concerned that even my WV Ford mechanic could notice a blower. Goll-ie, dats not right, I know dats not right, dat can't belong dere.
Wow - either the new SHOs have ultra-conservative programming with *much* room for improvement, or Doug is being pretty optimistic. To me it just seems pretty unlikely to be able to get 20-30 HP out of any stock car by tweaking with fuel and timing (unless they were horrible from factory). But in defense of the chip - I've heard it is necessary to get electronic programming when you do other mods on a 96+ SHO in order to deal with the OBD system, which doesn't like mods, and you may not get any gains at all otherwise. I'm not sure if this is an illustration to this fact, but I recall in MT they modified a 96 or 97 SHO and compared it to stock. It had a Borla exhaust (I can't remember what else, but it didn't have a chip). Well it was *slower* than a previously tested stock car. FWIW.
> A chip should be out in about five months, worth 20-30 HP,
Remember that despite the claims of 20-30 hp for many chips when the SHO first came out, real world experience shows they are not getting that much...10-15 is pretty good if you can get it.
> Sometime soon I'll rent rib retractors do the cone-otomy. How much is that worth performance wise?
I haven't looked at the gen 3 SHO to see what the intake tract is like. Have you checked out if it has the same removable cone as the others? HP increase in best case is maybe 5-8.
Timothy J. Wright
One reason we are so optimistic about HP is because the V8 pulls so strong in third but much less so in first and second gear. We think the car might be hobbled in first and second. Doug told me that the V8 SHO pulls 25 inches of Hg at idle, the basics are there to build HP. Doug is working on nitrous, blowers and turbos. We are both concerned about the ATX living once it starts getting 100 HP over stock if it doesn't get beefed up.
Latter on if we put on a blower or turbo we would have to get these basics sorted out first anyway. I thought I would try things that cost hundreds of dollars before I try things that cost thousands of dollars.
I hope if I can take car of the intake restriction, I am not aware of any major exhaust restrictions, that the chip could be pretty effective. Eventually, I do what ever it takes to get the V8 the respect of the V6 guys. Call the 30 HP chip my second favorite fantasy. We will know for sure days after the chip comes out. ;-) I'll share the dyno-numbers.
Five to eight HP at the rear wheel? That's ten at the flywheel, cone goes.
Has anyone ever contacted Yamaha about how to get the 300 HP that our engines had when they were given to Ford, and what Ford did to detune them?
I thought the reason that the 3rd gens were only at 235HP was because they had an overheating problem so they de-tuned them. (God, I hope I am not starting some big tread back up...)
The 3rd gen SHO is potent once at speed, this is Ford fault, but I would love to run one on the open road! There is suppose to be cooling problems with extra HP (as stated on the list) and Ford has made SHO HP speed related, so the faster you are going the more HP you get, hey MT & Auto-something-or-other said this! I agree that the 3.4l V8 should be more capable of 235 HP, look at all the other exotic small displacements V8 out there, then again they don't have the Ford ATX either!
Timothy J. Wright
3.4L is about 207 CID, One hp per cubic in is strong for a normally aspirated racing motor. 235/207 isn't that about 1.135 hp/cid? Add to the remarkable specific output, this is a relatively flexible street engine with a broad tractable torque curve and the output is outstanding. Then no 60K maintenance, the cam drives are chain-drive not belt and the tune up interval is 100K. The aluminum block is strong and light with iron bore liners. And the damn thing actually passes emissions? This is not a bad motor for a 4 door Ford sedan.
This little motor sucks, about 25+ psi vacuum at idle
to be exact. It fires right up, runs hard even when cold.
The V8 SHO uses OBD-II as part of its engine management system. This is a much more difficult system to modify than the preceding system (OBD-I). Many experts are predicting the death of aftermarket engine modifications due to the difficulty of working with OBD-II. Here's a rebuttal of that prediction and a ray of hope for owners of V8 SHOs.....
Thanks to Mike Davis.
Since the advent of engine management systems, there has been false testimony given against it at every turn. Interestingly, OBD has received an unequally large share of skepticism. Of course, it is understandable that the public-at-large would be skeptical of something that is being billed as "beneficial" to the consumer.
The fact is that OBD-II is simply an advanced diagnostic tool which provides more trouble-codes than before, and is capable of recording more intermittent problems. This helps the consumer by providing a quicker, more-accurate diagnosis of the problem, almost to the point of saying replace this part... it's not functioning correctly.
The only real disadvantage, is that the scanning tools will cost more, and the increased error checking will detect problems that it didn't before (i.e. the check engine light display quicker than before, which could be viewed as an advantage or a burden).
EEC-V operates independently of OBD-II in the sense of controlling the engine. That is to say that the actual control system gathers the inputs (within acceptable ranges) and determines the control outputs as best that it can, regardless of the fact that OBD-II is operating or not.