SHO me some heads!

[1993MTXSHO]

55hp is attainable from an entire top end kit, but spending 1800 on just the heads is not worth it. The EH/BBB intake, with a 69mm tb, and stage 2 cams will probably net about a 40hp gain. Take stock heads and throw in some oversize valves (not really fully necessary), and maybe do a mile hand port job yourself, you will be pretty close to the 55, maybe 45hp or so. But to gain about 15-20 hp on 1800 dollar heads is not worth it IMO. Now if this 1800 bucks included the BBB/EH, TB, heads, cams, etc, then it would definitly be worth it.

 

[NovaSS]

55 hp to the wheels?

 

[illSHOyou]

mister gude said if we can get a group buy to happen that he will do the work. i can see the disbelief that you all may have, but mind you these heads where designed about 20 years ago. im sure there are things that can be done to make the better than they are now. and 55hp just from the heads, well i dont think you even see that but putting on a nice set of afr 185 heads on a 5.0. but with cams and intake work and the other modifications mister gude will do, i think 55 is a reasonable number(tho i am no expert on this subject). as soon as i get a set of heads i am sending them off to him. ill will post under this thread with pics and what ever performance numbers i get.

I would think everybody would agree that these heads are right on par with many of the current offerings from manufuactures today if not better. I doesn't matter that there 20 years old. Thats just how good they were 20 years ago. The SHO engine was a race designed engine, not a regular sedan engine hopped up for race. 55hp is only going to happen if there are supporting mods, not just heads and cams. 55hp is very possible but carefull attention must be taken on the heads, cam choice, and the rest of the puzzle. Its going to put the porter to the test. I would diffenetly get him a SHO head in hands before he promises 55hp.

Trust me its not impossible, but how big is your wallet and time?

 

[illSHOyou]

I like what I see on the guy's website. I would be very interested if he took interest in the SHO engine. I would like to do huge valves, and some major port work myself.

Could you ask him what it would cost to flow bench different port configurations ? I would like to mess with the communication point in the head and see if improvements could be found. I would also like to look into valves so big that reliefs would have to be install at the edge of the camber. Special coatings, Valve train components, etc...

Also can he create a CNC program? If we pay to have the research done then we might as well make it repeatable and avialable?

I am very interested, but bottom line you probably wont convience anybody else on this forum without results, but with results many can join. Flowbench testing should be enough proof. If we can get the guy to spend the time with a head and different intake manifold configerations (BBB, Port Work, Large Throttle body, Bigger Ports, etc.) That might be the evidence you need.

So check his rates, I would abosolutely love to add input/parts/modifications to test... I would submit 3 parts off the top of my head for flow bench.

 

[supra dave]

when i was talking to mister gude i ask about bigger valves and some of the other things you had said above. he laugh a lil and said theres no need to spend that much extra money, but if you wanted to spend that money he would still do it. i am going for a street friendly head package. with most of the power mid to high rpms due to the SHO loven the mid to high rang. but i will still ask him how much extra it would be to do some of the thing you where asking about.

 

[1993MTXSHO]

IIRC The biggest valve you can fit on a sho head is about 37mm and that would really be pushing it. My oversized valves are 36.

 

[illSHOyou]

when i was talking to mister gude i ask about bigger valves and some of the other things you had said above. he laugh a lil and said theres no need to spend that much extra money, but if you wanted to spend that money he would still do it. i am going for a street friendly head package. with most of the power mid to high rpms due to the SHO loven the mid to high rang. but i will still ask him how much extra it would be to do some of the thing you where asking about.

I would just like to know my options. I would like to see how radical he can go at the same time. I might end up destroking and going as big as possible with the bore, so I would like to increase the valve cross-sections, unshroud the valves, either polish or coat the camber, mill the heads and bring the chamber closer to the cylinder deck, maybe cams...? Not sure, this is going to be a twin turbo setup...

Example of intake manifold work:
http://s264.photobucket.com/albums/ii185/SHOoffPlus/droptSHO/
I would really like to test one of these manifolds...

Head options, some radical head mods and cross over point adjusting and potential shaping...
http://s264.photobucket.com/albums/ii185/SHOoffPlus/SHO Head/

 

[illSHOyou]

IIRC The biggest valve you can fit on a sho head is about 37mm and that would really be pushing it. My oversized valves are 36.

What is the limitation in valve size?

 

[St Louis SHO]

The valves hitting each other.

 

[yamahaSHO]

Your valve seat will limit you before that. If you're going big enough to hit valves together, then you're not going to seal at all. You may be able to have larger seats fitted, but you'll never get your money's worth going that route.

55whp is roughly 65bhp. That's asking quite a bit with this small motor that's already doing pretty well as is. The biggest bonus to this motor is more its strength. It'll handle quite a bit of power, but it'll take more than NA in most cases to get that power. Revving the motor much past 8k is asking a lot too... The harmonics are much worse the higher you go.

 

[egroce11]

The SHO heads are good, but they are not perfect. You could very well get 55hp from the heads, but your going to shell out the cash and your going to spin the **** out of the motor.

The only way I could forsee getting 55hp is 3.2L destroked to 3.0L or maybe 3.1 Big Bore, and then alot of head work, bigger valves and +40 cams. Working rpm would probably be in the 6,500-8,500rpm range. The stock intake would have trouble with that working rpm unless radically modified.

I agree with you except the working RPM will be a lot higher. Stock intake will do alot more than alot of people think but he said Gude was going to open the runners and do BBB's.

You will still have good low end power and fantastic upper end power. As heavily modified as mine is, Ransom (sho_sc) was able to drive it down the highway, and we still haven't seen the end of the power in the upper end.

I would like to see what he gets for flow numbers thru the intake tubes and heads.

If I remember right, (I'd have to find it,) but I believe subaru valves 38mm? will work but you'd have to heavily modify the seats and if your bringing the pistons up for higher compression than the head valve reliefs would have to be modified.

The valve stuff might not be right it's from memory and thats shot right now.

Ernie

 

[illSHOyou]

I agree with you except the working RPM will be a lot higher. Stock intake will do alot more than alot of people think but he said Gude was going to open the runners and do BBB's.

You will still have good low end power and fantastic upper end power. As heavily modified as mine is, Ransom (sho_sc) was able to drive it down the highway, and we still haven't seen the end of the power in the upper end.

I would like to see what he gets for flow numbers thru the intake tubes and heads.

If I remember right, (I'd have to find it,) but I believe subaru valves 38mm? will work but you'd have to heavily modify the seats and if your bringing the pistons up for higher compression than the head valve reliefs would have to be modified.

The valve stuff might not be right it's from memory and thats shot right now.

Ernie

I just figured power would be shifted higher. I am sure the stock intake can work fine, but it diffinently needs to be gone through good. Destroking should lower the mach index at high rpm and make the stock cams carry the power longer, not to mention what +40 cams would do. If I could I would like to look at destroking the motor into a huge aftermarket piston/rod family. Maybe import aftermarket?

As for compression I would like to stay away from valve reliefs, stick to a flat piston, and mill the head bringing it closer to the deck. Milling the head could potential improve the flow into the cylinder, but i dunno.

 

[supra dave]

this is about what i will be getting for the head package. some things will be different due to the one of a kind heads and intake we have, but remember this is just to help give you all an idle and maybe to help me ask him somethings i may have not thought about.

1. Intake ports are ported to create maximum velocity then rough cross hatched to provide better fuel atomization, which increases combustion efficiency providing increased power both at low and high rpm.
2. Exhaust ports are ported to relive internal pressure quickly, yet provide enough velocity to scavenge well, insuring a full fresh fuel and air charge will be delivered to the combustion chambers, not diluted down with left over spent gases from the last firing.
3. Head surface is milled them hand lapped to create a multi directional #32 micro Finish surface, this leaving hundreds of micro ridges to be crushed down by the steel gasket forming a super micro barrier for better gasket sealing.
4. Intake to head ports are purposely mismatched or stepped to fight unwanted reverberation and to reduce boundary layer effects improving port flow.
5. Valve seats we have tried 3 angles so called 5 angle, and many other valve and seat combinations, we have found that the factory angle on the valve is overall the best and that the blended radius parabolic valve seats pioneered by Gude performance provides the most horse power and longevity on most Imports.
6. Valve guides in most cases we have found that shorting the valve guide is helpful and will promote increased flow while still maintaining excellent valve control.
7. Valve springs Gude performance camshafts are designed to operate to extreme rpm on stock valve springs, we spent countless hours designing and developing profile which will not require a high pressure valve spring which can cause added friction and valve stem failure due to the high loading of stiffer springs vale stem failure will usually cause major engine damage.
A few exceptions we will up the spring pressure 8000 rpm.
8. Camshafts Gude performance Bullfrog or Stinger cams are ground to precise tolerances, and are of the famous Gude profiles. Gude poured out all 30 plus years of experience, into designing cam profiles that are stable at extreme high rpm with stock or light valve spring loading, this increasing horse power and engine reliability, as high valve spring loading can case excessive wear and result in total valve stem failure destroying a expensive engine see article on this site.

9. THROTTLE BODIES Gude throttle bodies are bored and a new oversize butterfly is installed, this providing maximum flow and performance, with Gudes 20 years of throttle bodie experience Gude has developed a unique aerodynamic shape of the throttle bodie inlet barrel this not only improves flow but also throttle response this make for a great circle track, road race, or autocross throttle bodie, as well as drag racing.

 

[LOUDSHO92]

Don't mill the heads too much otherwise you will throw off the timing.

 

[illSHOyou]

Don't mill the heads too much otherwise you will throw off the timing.

The heads I got right now are milled at the maximium, but I am going to get the adjustable sprockets.

 

[Mike Kopstain]

when i was talking to mister gude i ask about bigger valves and some of the other things you had said above. he laugh a lil and said theres no need to spend that much extra money, but if you wanted to spend that money he would still do it. i am going for a street friendly head package. with most of the power mid to high rpms due to the SHO loven the mid to high rang. but i will still ask him how much extra it would be to do some of the thing you where asking about.

Here's your problem. As it is the heads outflow the engine they're attached. By further raising their flow capabilities on a naturally aspirated engine all you do is serve to raise your powerband with a nominal hp addition, most likely no more than 15 horsepower.

With a good set of cams you're probably talking a difference of 30 horsepower and that's assuming you already have the supporting modifications for the cams/ heads.

I'm sure everyone here appreciates what you're trying to do but there have been hundreds before that have tried to do the same at the behest of third party vendors, myself included at a much youunger age!

55hp isn't going to happen, isn't a reasonable expectation from ANY head design, and if you're expecting near this number you're mistaken. Don't confuse someone else's confidence in their own work for experience on a particular platform.

 

[shobote]

I Agree with Mikey; unless it is proven, all this work will empty your wallet and likely result in a less streetable engine that loses low end, and has to be revved before gains are seen; low and mid range torque is where it's at for street performance. Damage happens when you rev the **** out of the motor too....sorry, Ernie, no offense ! (e.g., Audi's low rev torque monster diesel kicks tail at race tracks.) What Yamaha supplied is a solid comprimise for streetability and durability with a broad torque curve and high revving.
Turbo = proven bang for buck with low/mid torque.

 

[egroce11]

I Agree with Mikey; unless it is proven, all this work will empty your wallet and likely result in a less streetable engine that loses low end, and has to be revved before gains are seen; low and mid range torque is where it's at for street performance. Damage happens when you rev the **** out of the motor too....sorry, Ernie, no offense ! (e.g., Audi's low rev torque monster diesel kicks tail at race tracks.) What Yamaha supplied is a solid comprimise for streetability and durability with a broad torque curve and high revving.
Turbo = proven bang for buck with low/mid torque.

No offense taken. I believe I figured out that my problem has something to do with the dual oil filter system I'm using. Just a quick hi-jack, micky if you've followed my car or read about loosing #5 rod bearing again, do you have any sugestions?

a question for the origanal poster, why all this work for a turbo. Mine is N/A and pulls as hard or harder than a small blower car. (not my words)

 

[illSHOyou]

Damage happens when you rev the **** out of the motor too....sorry, Ernie, no offense !
Turbo = proven bang for buck with low/mid torque.

Rev the **** out of the motor is not always the problem. Component matterial is most likely the problem. Destroking slows piston speeds down even further than stock. Piston speeds are already conservative stock compared to say s2000. Not only do piston speeds drop rod angle improves. The crank spins harder, vibration will increases, but were really not do the motor injustice for spinning harder. Valve train nine times out of ten is the motor speed limitation. The motor is very capable to spin almost to 9,000rpm with the right components. Who has the claim to fame with expensive pistons AND rods?

 

[supra dave]

ok, here is the thing, 55 may not be obtainable. but i will work with mister gude to reach that goal. i know that speed=money. i am prepared to do that, and hopefully it will give our community a good option for some more steerable, reliable, kick ass power. i am still looking for a set of head for the mtx to send off to mister gude. i talk to him this morning and i am fully confident in his ability, i hope to show you all that you can put the same confidants in him to. if everything works out like i know it will then we will have a strong ally in our quest for fun and affordable power. but he will not give out a bench flow test for good reasons which i understand and respect. as soon as i get the heads back i will do a bass line dyno for my car, then put the new head package on and see what comes up. if any one has a good set of heads, please contact me(i cant be out of a car for this, plus its just to much fun to drive to put out of commission for a month). thank you all vary much for reading and putting some good info in this post.