n/a computer with turbo eng.

[Roastin944]

Will a n/a computer run the top end of a turbo engine? with the n/a headers and manifold. All i am changing is the lower compression pistons, head and possibly the valvetrain and camshaft from a turbo. Can i use my n/a cam valves everything on a turbo head? I want to rebuild it to make it handle boost like the turbo but it will be supercharged, is the main thing just lowering the compression, or is the ceramic ports and whatnot the strong point of the turbo engine? What makes the turbo engine so much more reliable besides forged pistons and lowered compression. Thanks

John

P.S. Dont tell me to buy a turbo! I want some experience with fabricating a supercharger system, blowing up the motor, rebuilding it to handle boost reliably and maybe upgrading the system later!

[PorscheG96]

Originally posted by Roastin944:
I want to rebuild it to make it handle boost like the turbo but it will be supercharged, is the main thing just lowering the compression, or is the ceramic ports and whatnot the strong point of the turbo engine? What makes the turbo engine so much more reliable besides forged pistons and lowered compression.

I think what you're forgetting is the KLR. This is a key element of the 951 which makes the engine reliable under boost. You can lower compression and use whatever turbo components you choose but a big reliability factor is in the fuel/timing control. The KLR is designed to communicate with the DME, drawing timing back under boost and anticipating detonation [opposite of a knock sensor] based on boost pressure, load, temperature, and perhaps other conditions. The DME has vastly different fueling maps, too. A turbo/supercharged car requires multiple fuel maps in one...you've got the fueling before boost, a transition, and then fueling on boost. If you look at a good a/f curve from a dyno you'll see a bowl shape to the mixture...a supercharger may be easier to predict when fueling because the boost comes on linearly instead of all at once. Good luck!

[Scott R]

When I supercharged mine, and blew the first engine I just purchased a turbo long block for $400.

It was ten times easier than rebuilding my NA engine into a turbo block. Plus I found an 87 long block that had the updated tensioner.

[ae1969]

Roastin....

What you will need is something like the Ultrasafeguard units. The units will retard timing for you. They come with a knock sensor that you will need to tap into your NA block. They currently provide a GM or Honda sensor. You should be able to use the bosch knock sensor. I was speaking with Marksports and he figured that the bosch sensor may eliminate noise better on our porsche engines that are caused by those wonderfull lifters. To play it safe go bosch.

You will need an external ignition module as well to work with the Ultrasafeguard unit. You have a variety of choices here.

The N/A head can probably be rebuilt to handle boost for less money than buying a turbo head. You will have to shop around.

You will also need a way to get more fuel in there. You may have to go to a larger injectors or get an extra injector in the setup. I believe marksports is using some from siemens. It was thought a while back that the turbo injectors should be a straight swap, but the consencus is they are not.

You are definitely doing your homework. You are almost there.

Good luck

[Roastin944]

Thanks alot for the info, I am currently going to use a MSD boost timing master to retard the timing as boost increases, this is not a knock sensor which isnt the best but will retard the timing as i get boost so i dont detonate, Then i am going to use a 5th injector, a cold start injector for the fuel. Im sure after a while the engine will get tired if it does knock or detonate first and blow up. Then i wanted to put the forged pistons and maybe rods in there to handle it, do you think the stock valves springs, cam and everything will be efficient for 6 lbs of boost? What o one of those ultra safeguard systems run? Would it be better than a MSD bosst timing master? Thanks alot guys

John

PS - Scoot R- Did you run the supercharger on the turbo block? Did the n/a computer run it? Did the n/a headers and intake manifold fit on the block? How about all of the electrical, ect. Thanks alot

[Scott R]

[i]
PS - Scoot R- Did you run the supercharger on the turbo block? Did the n/a computer run it? Did the n/a headers and intake manifold fit on the block? How about all of the electrical, ect. Thanks alot [/B]

Yes I did run it on the turbo block. The lower compression pistons, and sodium filled valves were what I was interested in.

The NA header has gone through some changes over the years but my 85.5 bolted on. As for electrical I had to use the NA injectors, and I did not hook up the knock sensor. I also had to retrofit the oil return and feed line to mate to a smaller oil return line from Aeroquip for my Autorotor blower.

So essentially I used the turbo block hardware, and the NA running gear. I did not need any other engine management, but I did install H20 injection by Aquamist.

This solution worked fine at 5PSI. At seven I blew a ring on #2, might have been on its way out, I will never know. But I could have very much used an intercooler; if I ever did it again I would have purchased an intercooler to cool the charge.

With the blower modifications, and the lack of cold air into the intake, the engine would always run warm. A/C was not an option for me, if I ran it the car would start to overheat.

I think some of the newer kits also have to have the A/C deleted in order to complete the install.

Like I said in the end after it was all said and done I had a $10k 944 NA that was only worth 3k. So unless you want to be buried in this thing when you die, just hold out for a 951.

Also like Marksports, have you investigated beefing up your suspension? I found that the NA suspension did not handle the extra power very well. Looks like Porsche designed it for a certain torque range and speed.

[ae1969]

I think 5-6 lbs of boost should in theory run on the N/A's high compression engine.....

First of all when measuring boost pressures it really makes a difference where you do the measuring. I have to tell you their are wonderfull books out there as well as most sport compact magazines have some great write ups. Boost can range upto 4 lbs depending where you measure on an engine. So an engine just barely running 6lbs may infact hit sustained peeks of upto 10lbs which could in fact blow your engine to ****.

The problem is that not many aftermarket tuners have looked at the 944's setup. Frankly their is no market for it compared to all the civics out there. No one has really found the optimal way to set up the 944NA. Even the 951 has some limitations when it comes to its setup.

I think the head may handle the 5-6lbs but for how long that is the million dollar question. When looking at any boosted situation you should always look at the worst case scenario.

I have seen many stock vehicles run 6-8 lbs of boost with no problem. Mustangs, camaros, civics etc.... but those companies have put a lot of thought into their setups.....and probably a truck load of blown engines.

The best thing you can do is create as many safety measures as you can. Lots of good fuel, timing retardation, knock sensing, boost levels set low, extra injectors, forged rods/pistons, upgraded heads, water injection? etc.....

The ultrasafeguard v.01 I have cost me $400. John who is the owner of ultrasafeguard knows engine retarding like the back of his hand.

Good luck in your project....

[PorscheG96]

I'm running 4 psi on 11:1 compression non-intercooled and the knock sensors are pulling back the timing at 2800 when full boost hits. I had the car on a dyno long enough to get an a/f reading but haven't boosted the car much since then. The car just needs more fuel. Running the car without a knock sensor will destroy the engine fast...that's probably how Scott blew up. There's no way a headgasket, piston, block, or anything else can hold up to the heat and pressure of detonation.

I've never heard my car detonate [believe me I've been listening] but I know that the engine is hearing it because of how the acceleration FEELS. It runs very strong until full boost comes on and then the torque goes flat...timing is being pulled back big time. You should be able to run 6 psi boost no problem, even more intercooled with the 9.x:1 NA pistons. The bottom end should be more than able to handle the power because inertial loads on the engine are FAR greater than loads produced by more torque.

The MSD unit is a good idea, you can program timing retard to operate at different RPM's, this shouldn't be too hard to figure out with a supercharged engine since boost delivery is linear over the range. The NA cam might give a bit more overlap than you'd desire with a boosted engine but I'm guessing it'll work fine. The 951 sodium filled valves and ceramic coated ports just prevent exhaust energy from being lost before spooling the turbo, this shouldn't be a problem with a supercharged car. You'll probably want to run colder spark plugs though.

[marksportcts]

Go for the Ultrasafeguard as it incorporates the knock sensor with a boost timing retard. It will retard timing when the built-in map sensor gets boost, and more if it starts to knock. I takes twice the timing retard to stop knocking than to prevent it.

http://www.jandssafeguard.com/safeguard.html

I may have posted this already, I currently not running the two 440cc additional injectors. I am running 440cc on the rail with the Link MAP kit.

[Roastin944]

Thank you everybody for all the great advice, i'll let everyone know how it goes and i'll post some pictures...

Thanks again

John

[Scott R]

Yea, no knock sensor was included with my kit, plus the manufacturer "Rimmer" went out of business after I installed it!