Calling all gearheads: want engine build advice/opinions

[General Stalin]

Alright, well some of you may know that I have been in the process of building a new engine for my truck (for the last month or so it has been on the back burner as I try to save up more money to put aside).

Now, I decided to lay out my plans here and hopefully get some good advice or at least hear some knowledgable opinions on what to do. I'm totally open to any changes or suggestions anyone may have, so don't be afraid to give some constructive criticism.

I'm building a budget street/strip 355. I don't have all the money in the world to dump thousands on some sick and twisted 500 horsepower monster, so I am doing almost all the work myself and trying to find cheap but reliable parts and methods that will still give me the power I want. I'm shooting for at least 330+ horsepower, but believe me... the more power I can get for the money, the better.

Here is the plan:

-I got a 350 block out of a 1993 Silverado 2500. I already stripped that and sent it to a very reputed engine shop. they have cleaned it and bored it .030" oversize, so now it is a 355.

-Cast iron Vortec cylinder heads

-New cast steel crankshaft

-Hyperutectic pistons w/ moly rings

-Keeping the old connecting rods from the engine

-Holley 670 CFM Throttle Body Injection unit

-GM Performance parts TBI Vortec intake manifold

-Lunati Voodoo Hydraulic flat tappet camshaft/lifters http://store.summitracing.com/partdetail.asp?part=LUN-60101LK&autoview=sku (Keep in mind, for budget reasons, I kind of want to stay away from getting a cam that will require me to get a new stall converter). Haven't given a whole lot of thought to springs, seats, conneting rods, or any of that crap just yet.

-Full Mallory ignition system (ignition box, distributor, coil, wires)

-Obviously, a full 1996 350 5.7L gasket set with bearings for the Vortec-head engine

-I am also going to reuse the Edelbrock headers I have on my engine right now

Pretty much all the accesory pullies and such I'm going to try and just reuse from the engine I have in my truck now. So that is it pretty much. I haven't decided if I should get a deep oil pan or not, or what I should really do with that. Maybe just get and OEM oil pan?

I honestly don't know how much power this setup would make... not in the least. I mean, I assume it should get me up in the 330 horsepower range at least? I would like to get my hands on a 4L80E, but if I can't happen to get lucky and find one out of a 3/4 ton or 1 ton truck from the boneyard, then I'm going to just put and automatic/manual valve body shift kit in my 4L60E along with a couple servos.

Also, computer suggestions are very welcome too. Who should I go to for making me a new chip? Should I get a seperate controller for my transmission? How would I go about doing all of this? Etc.

Any help, tips, suggestions, or just opinions on this would be awesome.

 

[95TwinTT]

In my opinion, the short cut to happiness, is find a used supercharger setup. I sold the one from my 95 Tahoe, complete for $500. They are out there and it is a way to get the power you want without any screwing around.

With N/A every little tiny detail has to be just right to get to the big numbers. When you push the air in, it doesn't make much difference what heads you have or what size valves, or whether you have headers or not. It just goes.

The Vortech set up for the throttle body had a spacer block with two injectors that are controlled by a stand alone "black box", that simply follows manifold pressure and adds additional fuel.

You don't have to mess with your computer, or do anything except enjoy the ride. The only thing you need to be careful of is getting carried away.

Once you see how easy it is to make good power, you want to make MORE. If you can just stay with stage one, you will have lots of fun and not spend so much time under the hood.

Just my humble opinion. Seems like in the long run it is much cheaper than chasing the N/A ghost of power. :thumbsup:

 

[General Stalin]

So you are saying I won't have to upgrade my computer even though I will be using a higher flow setup? I always thought that the old OBDI computer would have to be reset with different fuel maps seeing as how the throttle body and heads will be allowing much more flow, which in turn, means more fuel.

As for super charging, is it really that simple? I could super charge my engine decently without having to change a lot of other components or alter anything?

Thanks a lot for the reply, I was starting to think their weren't many gearheads in this place as I watched my topic plumet pathetically to the bottom of the page. Your input is very appreciated. I always saw you as the real tuner guy here, I'm glad to be getting advice from you as it seems you sure to have an amazing wealth of knowledge when it comes to this kind of stuff, especially seeing as how you have an insanely tweaked 1995 Tahoe.

 

[95TwinTT]

I have been using the Vortech line of supercharges. They make the kits to bolt onto stock engines. They know how much additional air the blower makes, so they add the injectors and the control to turn them on.

My first blower on the 95 Tahoe was bolted directly onto the stock engine. That included the lame heads that adorn the 95 sluggish engine.

I was thrilled to a nub with the performance. Then curiosisty got to me and I started screwing around with different size pulleys. Before long the original blower kit was needing some help in the computer department, because I had pushed it up over 12 pounds boost.

I imagine it is something close to a drug addiction. If you can leave it as the original kit without messing with pulleys, it is fine with the stock tune.

Then again, with the parts you have already rounded up, you would be way ahead of the game.

It's not for everybody, but it seems like you are setting in the middle of a project getting ready to load the parts cannon.

I have had a lot of different performance engines through the years, and now that I'm in the "boost" catagory, I can't go back. N/A is too boring, unless you take it to the edge. Then you have an engine that won't idle very well, because the exhaust valves and intake valves are open at the same time. lol

The other thing about forced induction, you can run quiet if you want to. I have had a lot of fun in the past few years with both the 95 Tahoe and the 94 Camaro. They appear close to stock from the outside.

Anyway, I was just suggesting a alternative to the same path traveled by so many. It cost nothing to just look into it. Ebay often has superchargers. They also have the TCU transmission control units, occasionally. I have seen them go from $150 - $250.

The other half of making your 3 ton truck more responsive is to take advantage of a higher stall speed TC, without getting crazy. They come with lockup, so with a TCU you can control them well and have economy while going back and forth to work and performance when you get on it.

I'm not selling anything here, just offering some ideas. Just keep in mind that engines are nothing more than glorified air pumps and I have found that that old saying holds true that, "if it isn't blown, it sucks". :cool2:





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[General Stalin]

I am definitely taking your advice to heart, don't think your words are falling on deaf ears. Just keep in mind I'm trying to keep the investment cost down (at least for the time being... I'm sure I will tack plenty of cash on to this project down the road once the engine is built and installed). Like I said, I was trying to stear clear of spending hundreds of dollars on torque converters and such, which is why I did not pick out a really extreme camshaft.

 

[JKmotorsports]

Even if you don't go wild on the cam profile, a slightly higher stall converter will help to get that heavy truck up to speed much quicker than the stock tq. And I'd definitely have to agree with 95TwinTT. For the money/power ratio, f/i is the way to go.

 

[General Stalin]

Hmm... well now you guys have got me thinking different paths. If I go with a supercharger, then I would not be getting the Holley TBI, and I would probably be getting a totally different intake manifold (maybe a cheaper one? Or do a lot of super charger kits come with them?).

After doing a little research on the effects of a higher stall TC, it seems like it would be a very smart investment. Thanks for telling me about the benefits. I just hate to have this project get pushed back further and further. What was originally going to be a summer project is turning into a summer/winter project. This truck probably won't see this engine 'till early spring. Great things take time though, I suppose. Rome wasn't build in a day, isn't that what they say?

 

[JKmotorsports]

....

After doing a little research on the effects of a higher stall TC, it seems like it would be a very smart investment. Thanks for telling me about the benefits. I just hate to have this project get pushed back further and further. What was originally going to be a summer project is turning into a summer/winter project. This truck probably won't see this engine 'till early spring. Great things take time though, I suppose. Rome wasn't build in a day, isn't that what they say?

Just my .02 from experience; take your time and don't rush anything. Don't just deal with something for now because you want to hurry and get it done, or because your current budget won't allow you to get it done as quickly as you'd like. With engine swaps, builds, and f/i add-ons, it's best to take the time to research and analyze what it's going to take to get what you really want. The extra time you spend on research and putting things together in a complete solution will pay off.

 

[Paul Greathouse]

General, hope you don't mind me hijacking your thread here for a minute, but this is just way too interesting. I don't know much about superchargers but want to learn.

95TwinTT
I recently bought a totally stock 95 2dr 4wd Tahoe and yes it's motor is sluggish. The motor has 103,000 miles on it and runs really smooth but it could sure use some help in the get up and go department. I have a few questions.

Does a blower benefit you during normal driving or only when you really need that extra boost?

Does the blower operate any time the engine is on or is it engaged and disengaged as needed?

If I get the blower kit for a stock engine like the first one you had, how much of a power gain will I notice?

Last but not least, with gas prices what they are these days, how much (if any) of a negative effect will the supercharger have on fuel economy? If I drive reasonably, can I use the blower at all times and gain some power without sacraficing fuel economy?

The higher stall torque converter sounds interesting too. Could you elaborate some on how the higher stall TC increases performance. With the mileage that my truck has a transmission rebuild could be in my future within a few thousand miles anyway. Sounds like a good time for the TC upgrade.

 

[95TwinTT]

General, hope you don't mind me hijacking your thread here for a minute, but this is just way too interesting. I don't know much about superchargers but want to learn.

95TwinTT
I recently bought a totally stock 95 2dr 4wd Tahoe and yes it's motor is sluggish. The motor has 103,000 miles on it and runs really smooth but it could sure use some help in the get up and go department. I have a few questions.

Does a blower benefit you during normal driving or only when you really need that extra boost?

Does the blower operate any time the engine is on or is it engaged and disengaged as needed?

If I get the blower kit for a stock engine like the first one you had, how much of a power gain will I notice?

Last but not least, with gas prices what they are these days, how much (if any) of a negative effect will the supercharger have on fuel economy? If I drive reasonably, can I use the blower at all times and gain some power without sacraficing fuel economy?

The higher stall torque converter sounds interesting too. Could you elaborate some on how the higher stall TC increases performance. With the mileage that my truck has a transmission rebuild could be in my future within a few thousand miles anyway. Sounds like a good time for the TC upgrade.

First a word of caution, an engine with 103,000 miles will certainly have a faster trip to the point of needing a rebuild by strapping a blower on it.

I installed my first one on the stock 95, when the engine only had 30,000 miles. The Kit was new from Vortech. It took about a day for the installation. The first impression was absolute acute euphoria.

The most interesting thing was that the gas pedal was extremely sensitive instead of being a delayed reaction, it was alive.

The supercharger is belt driven, so it is ON all the time. It obviously blows more air the faster it turns. The big difference is when you first crack open the throttle plates, there is about one pound of air waiting to rush in. That added air makes good use of the normally rich mixture that these vehicles are programmed with.

Part of the kit is a spacer block, that goes between the throttle body and the intake manifold. It has two injectors in it that are controlled by a stand alone “black boxâ€, supplied with the kit. It pulses the injectors based on manifold pressure. As the pressure goes up, the injectors follow, increasing the fuel to match the added air.

I don’t remember the exact numbers, but the added power was something like 125 hp.

The stock engine has higher compression ratio than you would normally want for building up a blown engine. Stock is something like 10 to 1. My current engine is 8 to 1. That lower compression ration, gives me more room to put more air into the engine before hitting the “too much†mark.

Fuel is the other key to this forced induction issue. With intake air being forced in, the combustion chamber pressures are much higher and pre ignition or pinging will occur unless the fuel octane is increased enough to keep it from firing before the spark.

So back to the basic issues. It would turn your truck into a totally different animal, but, you would be putting the aging stock engine at risk and also the trans may be finished off, by being asked to handle the added power.


On to TC’s. The torque converters are one of the greatest secrets of all. Problem is the really good ones will make a mess of $1,000. What is happening is, technology has come along in the TC department where they can actually multiply torque. Look at it as adding more horsepower to the engine, except the transmission is adding the power.

The higher stall speed, allows the engine to get further into it’s torque curve while working. You can see extreme versions of that at the drag strip. They get up to 4 to 5,000 rpm stall range. That is where you see a lot of wheel stands off the line.

I use 3200 stalls in my vehicles. It is very mild, but I don’t think you would enjoy the entire benefit of the high stall speed, without a separate controller for the trans. I use the TCI TCU, which allows me to customize the trans controls for shift points and TC lockup parameters. Plus a lot of other refinements that help the transmission live longer.

The 95 Tahoe has the OBD1 computer which is a nightmare to alter. I don’t mind doing a little wiring, so I just jumped in with the stand alone.

Let’s face it, these 6,000 pound trucks are never going to be fuel misers. The supercharger could allow a better fuel economy if you could keep from sticking your foot in it. When you are just driving normal, you will have a lower throttle setting, from where you are now, because of the added air being squeezed in.

You will also be buying premium instead of regular, so keep that in mind. I was not interested in economy, I just wanted to get the pig to move. I also didn’t care much what it cost. To me, spending $20,000 dollars on a 95 Tahoe is more fun than buying a new Tahoe for $40,000.

I personally think the older ones were built a little better. I know the doors on the 95 close like a bank vault. My wife has a 01 Tahoe. It is nice, but does not seem to have the same quality in the body.

I just went over 50,000 miles on my 95, so it will last me for a long time. I highly recommend forced induction, but I also caution folks that the added power is great fun but does cost more money. It is also intoxicating. I am still tweaking my 95. The setup I have in the Tahoe right now is capable of 1050 HP if I turn the wick up. I’m setting at 12 psi boost right now, but will be taking it up to 20 psi in the near future.

 

[Paul Greathouse]

95TwinTT, thanks for all the info, but as in most cases more info leads to more questions.

I want to keep my 95 around for a long time and I am also willing to spend some extra cash to get it to perform better. I checked out your link, that is some awesome stuff under the hood and in the exhaust department.

I don't need near the horsepower potential you have. I would be more than happy with the 125 or so that you gained with your first system.

I checked out Vortech's website but didn't see any prices I also looked at a couple of the sites for their recommended installers but didn't see anything there either. What is a rough ballpark figure of what a basic system would cost for my 95?

I'm willing to risk going into the engine early if the blower overloads my 100,000+ motor and I will probably be rebuilding my transmission soon anyway, the reverse gear is getting slow to engage. I don't plan on running it hard I just want it to accelerate at a reasonable rate when I step on the gas, I'm not getting that now. It’s especially bad when I run up behind someone on the interstate and have to slowdown and then speed back up. It seems like it takes forever for it pick back up. I've been driving the same motor in a 3/4 ton pickup for the last 12 years but it has a manual transmission. I'm beginning to think that allot of the shortcomings can be blamed on the automatic transmission in the Tahoe.

I have a local transmission shop nearby that’s run by a hotrod guy that likes to do hopped up transmission work. I'll talk to him about the torque converter stall speed changes that you mentioned. Is there anything special that I need to ask him for?

If I purchase a Vortech blower for my stock engine and the engine dies early, will the same blower kit work with a slightly bored crate motor?
Or, should I be asking if the OEM chip will still work with the combination of a crate motor and the blower kit?

 

[General Stalin]

Well, as far as buying a new super charger kit, expect to spend absolutely no less than like $1,300. I've looked at prices a bunch, and it is an expensive setup, there are no two ways about it. I would be weary of buying a used super charger because there is no certainty of what the porevious owner really did to it. It would become very costly if the charger failed and had to be rebuilt or something.

You say that the Vortech kit you had came with a spacer plate complete with injectors, so are you saying that the super charger kit you used actually ADDED two new fuel injectors to the current dual-injector setup on the TBI, or does it replace the stock injectors? If it ADDED injectors, then I would figure there would not be much more fuel economy to be had when using more gas.

If I purchase a Vortech blower for my stock engine and the engine dies early, will the same blower kit work with a slightly bored crate motor?
Or, should I be asking if the OEM chip will still work with the combination of a crate motor and the blower kit?

I believe both these question can be answered the same. I would figure that the crate motor you intend on buying would have to be about the same as the stock motor you had in before. You would want to buy a 350 or 355 or something, with nothing too radically different about the setup. If you had the supercharger that was for stock engines, then you would need to keep it throttle body injection I assume, and the OBD1 computer does not (adapt) to newer engine hardware, so if you go heavy on the cam or heads or something, then the computer would not be able to give you the right fuel because it would be getting different feedback from the sensors than it is programmed too.

I'm beginning to think that allot of the shortcomings can be blamed on the automatic transmission in the Tahoe.

Well, these 4L60E's were facotry built to be comfortable cruiser's, not tire blazing, hard launching gear boxes. A lot of it has to do with the computer control and the valve body in the stock 4L60E. They shift slow and there is a lot of overlap, there is also considerable delay. This makes for a very smooth and soft right, but not a very high performance one. Ways around this are shift kits, servos, and, as TwinTT is suggesting, a computer controller upgrade. these will also make your trans have an extended life because the factory settings for these transmissions are not good for them. the considerable overlap and such does not do any good for the life of the transmission.

Now I have somne more questions:

You said that you have to keep compression down to run a supercharger. Well how much compression would be allowed? The setup I'm looking at building will probably be in the 9.5 - 9.7:1 range. If I officially planned on going forced induction, would I need to plan on getting deeper dish pistons to get the compression down even lower?

What would you say would be an ideal stall speed for the engine in intend on building for my truck?

Would getting a stand alone computer use your old stock sensors, or is that an entirely new can of worms that would need a completely new engine wiring setup? I still have not figured out the best and most cost effective route for my computer area, as I am surely going to need to change the computer in some way to make up for the engine changes I will be making.

 

[95TwinTT]

Yes the Vortech did come with two additional injectors. Those two extra injectors would not do anything until there was a positive pressure in the intake manifold.

That means that they would not activate at all until you would “get on†it. The intake manifold is still going to be on the vacuum side when driving in normal city traffic.

Any addition of power to your engine will require more fuel. Gasoline has X amount of Btu’s per gallon or how ever you choose to measure it, minus friction and all of the other power robbing details of the internal combustion engine.

I used the original Vortech blower for the second version of the engine, which was a 383 stroker and port injection setup. I just changed the pulley’s to take it up to 15 psi. I also had a different manifold for the port injection. It was then that I added the Tec3 Computer to run the engine.

As far as getting a used blower, I sold my entire setup, for $500 and it was freshly rebuilt by the factory. The deals are out there, but it takes some looking to find them. If you can see a blower in person before buying, it is easy to tell if there is a problem with them. Buying from the Internet can be a crap shoot as you know.

The compression ratio you have will be the factor that will control how much boost you can use. The stock application was something like 6 pounds of boost. When I took my boost above the stock setting, I was blended E-85 with regular gas to get the octane I needed. If I was heading to the drag strip, I would get some unleaded racing fuel. There is a place in town that has 111 octane unleaded.


If economy is where you are headed, don’t even consider the blower. I say that, because you will not be able to help yourself from being infected by the “forced induction virusâ€. You would find yourself looking for more ways to continue to increase the power. I have seen it happen over and over with friends.

Here is another idea to ponder. I’m thinking about doing this myself, just for fun. If you build an engine exclusively for E-85, You could run the engine at 14 to 1 compression or maybe even higher and get a ton of power from a N/A engine.

The only problem being, you could NOT run it on gasoline, EVER. You hear people complaining about not getting very good mileage from E-85 in their flex fuel vehicles. That is because they are using engine setup for GASOLINE. E-85 needs to have higher compression to take advantage of it’s power.

Race cars have been burning alcohol for years and they do just fine at 14 to 1. I think that NASCAR gets around 800 hp from the small blocks they are running. And they are just carburetors and normally aspirated.


On to Transmissions…… If you are going to rebuild a 4L60e, it is a good idea to take advantage of some of the aftermarket heavy duty parts. Like the clutch pack with extra disc’s and a higher pressure pump. And of course a higher stall speed TC.

You cannot fully realize those enhancements without going to the TCU to control it. I have gotten into the TCU’s to the point where I have a transmission pressure gauge, built into a pillar pod to keep an eye on what the trans is doing and to make the programming with the laptop easier.

Even if you did nothing to the engine, the trans rebuild with a higher stall speed and intelligent controls, would make a noticeable difference in performance. Not to mention economy.


Keep in mind that the 95 Tahoe was setup to be a low rpm engine. The tach is red lined at something like 4500 rpm’s. Your truck has probably got a 3:42 to 1 ratio in the rear end. I would take it to at least a 4.10 to 1.

I changed my truck to 4:56 gears to help it get moving. Now that I have a 4L80e trans, it helps with the taller 1st gear than the 4L60e has. The 4L80 is like a close ration 4 speed manual for spread between gears.

After market computers to run the engine are available at many levels. I was looking for something that would grow with my changes. The stock sensors will work with some of the aftermarket computers, it just depends on what they are looking for.

I have had several different setups in this same truck. I did not start this journey of different engine combinations with any plan in place. I should have, but I was just messing around. I did learn that Nitrous is fun, but dangerous. I passed that stage quickly and got back to reality.

Once again, I’m not trying to push any one idea. I have just tried a lot of different things and have some experience to pass on for those that are interested in not making some of my same mistakes. Lol

 

[95TwinTT]

95TwinTT, thanks for all the info, but as in most cases more info leads to more questions.

I want to keep my 95 around for a long time and I am also willing to spend some extra cash to get it to perform better. I checked out your link, that is some awesome stuff under the hood and in the exhaust department.

I don't need near the horsepower potential you have. I would be more than happy with the 125 or so that you gained with your first system.

I checked out Vortech's website but didn't see any prices I also looked at a couple of the sites for their recommended installers but didn't see anything there either. What is a rough ballpark figure of what a basic system would cost for my 95?

I'm willing to risk going into the engine early if the blower overloads my 100,000+ motor and I will probably be rebuilding my transmission soon anyway, the reverse gear is getting slow to engage. I don't plan on running it hard I just want it to accelerate at a reasonable rate when I step on the gas, I'm not getting that now. It’s especially bad when I run up behind someone on the interstate and have to slowdown and then speed back up. It seems like it takes forever for it pick back up. I've been driving the same motor in a 3/4 ton pickup for the last 12 years but it has a manual transmission. I'm beginning to think that allot of the shortcomings can be blamed on the automatic transmission in the Tahoe.

I have a local transmission shop nearby that’s run by a hotrod guy that likes to do hopped up transmission work. I'll talk to him about the torque converter stall speed changes that you mentioned. Is there anything special that I need to ask him for?

If I purchase a Vortech blower for my stock engine and the engine dies early, will the same blower kit work with a slightly bored crate motor?
Or, should I be asking if the OEM chip will still work with the combination of a crate motor and the blower kit?

I have not been looking for these things for some time now. It is possible that Vortech no longer makes this kit, just because of the age.

It would probably have to be found on the used market and rebuilt.

As far as using the Vortech on a crate engine, it may be cheaper to just rebuild the engine you have. That is what I did. Then at least you know what you have. Check around your area for engine shops and ask some questions.

I like my engines done by people that at least speak english. lol

Any thing beyond strapping one of these stock blower kits, would most likely need an aftermarket engine control computer. You may not want to go that far. I don't know of anyone programming OBD1 units for blowers, but maybe someone can do it.

I got a Tec3 specifically so I could do my own programming with ease. I got tired of going to speed shops to have my computer tweaked on my comaro.

Hope this helps............. Good luck

 

[General Stalin]

Well, I have looked around very extensively on ebay and craigslist and definitely can not find a supercharger for L03 throttle body injection, let alone one for a low price. Unless I changed my entire setup and went carbeurator and no computer, which is not what I want to do, or went with an aftermarket (or vortec) fuel injection system which would cost me a lot of money.

I'm thinking the whole forced induction fantasy can wait until a ways down the road when the engine is already build and such.

If I end up getting a higher stall converter, I wonder if I should think about getting a more aggressive cam. the cam I have picked I feel is really mild. I would love to go with a full roller setup, but once again, that is way pricey. A roller tappet and cam setup is at least double the price of any comparable flat tappet setup.

I have read that there are some really good companies that burn custom chips for you at a low price, or you can learn how to burn your own chips. It may be a lot cheaper than buying a whole new computer.