The calm before the storm........

[bballr4567]

Yea I can bet that its running really rich. You doing the tune or having someone do it?

[lastyear4gt]

Nope there is a guy not far from me that is doing it. I dont have the money/experience to tune it myself yet.

[lastyear4gt]

I talked to the tuner today and all is good. He has tuned for the maf, injectors and all other modifications. He said at 6500RPM, the boost tops out at 9PSI on the 2.6" pulley. Apparently the car is very responsive and pulls extremely well. He was telling me that he did a 3.4 RSM centrifugal supercharger a couple months back and my kit pulls much harder and boosts much sooner than that one did.

I do however have a problem with knock. He was telling me that he has to take it out today and adjust the timing to eliminate the knock. The fuel pump pressure is not an issue as he figured it would, so he's not going to recommend even a re-wire at this time.

The only recommendation he made is that I save up for a couple weeks and come back for an alcohol injection kit. Droping the intake charge temp will allow me to not only run more timing, but will also help with fuel consumption and will almost eliminate the knock. I didnt realize this but, he was saying with his kit all you do is tee into the washer fluid jug and run the lines right from there, which makes sense seeing as all washer fluid is is water and alcohol. I think that will be my next and last step this season. That should put me well into the 13's.

Any suggestions? How much should a really good kit be? He told me $3-400 not sure if thats installed or not.

[AaronGTR]

Yeah, you would get boost much sooner with a roots blower compared to a centrifugal blower. That's normal.

Schweppe used alky on his kit. It does work, but it has it's downsides. Biggest one is you have to keep filling it all the time. The alky raises the octane and cools the air charge so you can increase timing, but if you have the timing map set in the pcm for the alky and it runs out you'll get crazy KR until you refill it. Personally I would tune out the knock without using alky. Our motors are actually quite detonation resistant compared to L67's, and I almost never get any knock. If you're using the highest octane gas and the right plugs you should be able to get rid of it with minor tweaking of the timing.

Oh, and 6500rpm is pretty high to be spinning the motor and blower. It's also the max for the trans, so I wouldn't go higher than that, and it might be a good idea to back it down a bit. It could also be causing the detonation if it's over 6k rpm, so find out where the knock is. Find out where the shift point is too. If it's too close to the redline, the engine will over rev between shifts at that power level before the trans re-engages, and you'll hit the rev limiter. That could cause detonation and makes the shifts seem to hang. Your shift mph should be set so they happen around 6100-6300rpm so you have some run out room. Those are just my suggestions... I don't know what all your tuner has changed already.

[bballr4567]

Yea not knowing exactly what the tuner is changing is kind of a bad thing, at least for me. Which is why im REALLY REALLY happy that I got a DHP and am learning exactly what my engine will do and how it should react. Its also a really fun and informative process.

[O1GAGT]

I have seen several instances where alcohol injection can strip the coating off of the rotors. I believe a few GP guys have seen this and I have seen it first hand on a few Downing Atlanta kits for BMW M42/M44 motors.

Just something to consider.

[lastyear4gt]

I could tune it and in time I too will have my own tuner.

As far as knock, I cant remember how high it was but he said it spike really high only once and thats it. But that could be caused by anthing, not necessarily the combustion process. I am running 94 octane which is the highest you can get in Canada and only from Sunocco. I hope the USA has 94 alot more accessiblewhen I drive to FLA for the honeymoon. Come to think of it, the knock may also be caused by the fuel. I filled the tank with fresh 94 before I took it to him, but the car also sat for the winter with gas in it, may have gone a little bad. Maybe Ill run a few tanks through and then take it back and see if he can advance the timing a little more then.

Like I said though, he is tuning the knock out, which I would imagine won't take too much timing out, and I can add the alchy injection at a later time. The only reason I am considering this is that it would be a cheaper/lighter option to and A2W intercooler and would allow me to run higher boost in the long run. I do see your point regarding the alcohol running out issue, but as long as I am spraying out of the washer reservoir, I have a low washer light and as long as I keep a jug in the trunk at all times I will be OK. When the light comes on, you just back off the throttle.

Eitherway, I pick it up tomorrow, ill drive it for a while, do a few 1/4 mile passes, save some money and think about it. If I feel I want more power, than the injection kit will go in.

BTW, I know there has been alot of talk regarding max boost on the eaton, but with a alchy kit/intercooler how high has anyone boosted with it?

[lastyear4gt]

Originally Posted by O1GAGT

I have seen several instances where alcohol injection can strip the coating off of the rotors. I believe a few GP guys have seen this and I have seen it first hand on a few Downing Atlanta kits for BMW M42/M44 motors.

Just something to consider.

The rotors? If you are reffering to the supercharger rotors, than there is a problem. Alcohol is meant to be sprayed after the boost before the intake manifold.

However, I can see how that would be a problem on the GTP because in that instance the alcohol kit is installed in the way of a plate between the charger and the intake and, yes in that sitaution the alcohol would get to the rotors. But with this setup, the alcohol would not likely make it to the rotors.

[O1GAGT]

Originally Posted by lastyear4gt

The rotors? If you are reffering to the supercharger rotors, than there is a problem. Alcohol is meant to be sprayed after the boost before the intake manifold.

However, I can see how that would be a problem on the GTP because in that instance the alcohol kit is installed in the way of a plate between the charger and the intake and, yes in that sitaution the alcohol would get to the rotors. But with this setup, the alcohol would not likely make it to the rotors.

Cool, I forgot that the GA system is setup a little different than the other vehicles that I mentioned. In that case alky injection would be a great addition.

[AaronGTR]

Yeah, the alky wouldn't cause any problems because it would be injected after the blower. Also I don't know if our blower would have any trouble with it because we do not have the abradable coating on them like is optional on some of the newer eaton blowers. I guess it depends on what coating is on them.


Anyway, if you filled the tank with high octane but haven't run it thru several times then yeah there certainly would have been some low octane mixed in there and that could affect it. I'd run a tank or two thru before finalizing the timing settings. Maybe have him dial the timing back a tad to be safe until then... then do the final tuning when you know you have good fuel.

I wouldn't worry about trying to run any more boost from that blower though even with an alky kit. That's always been the problem with this kit, is that the blower size limits the output for this setup. Schweppe pretty much maxed his out which is why he switched to turbo. With a 2.6" pulley and 6500 rpm you are already spinning it just over the max efficiency range that eaton recommends. Some people have run as low a 2.2" pulleys on it, but you are over spinning the blower and get diminishing returns, just making a lot more heat and eventually burn out the bearings on that b!tch. Basically if you get it into the 13's at 9psi and it's dependable and drivable, be happy with it! If you want more than that you should've gone turbo in the first place.

[bballr4567]

Yup. Just got to build up the engine now.

[SpyhunteR]

the damn Eaton blower is only good for 13's.

Turbo or bust.

[gectek]

nah, just put 2 tornados in the intake and one in the exhaust for good measure and itll be in the 11s in no time

[Z3R0]

I missed something i know, but what kind of SC did you use....M90?

[KhellendrosxS]

Originally Posted by lastyear4gt

I could tune it and in time I too will have my own tuner.

As far as knock, I cant remember how high it was but he said it spike really high only once and thats it. But that could be caused by anthing, not necessarily the combustion process. I am running 94 octane which is the highest you can get in Canada and only from Sunocco. I hope the USA has 94 alot more accessiblewhen I drive to FLA for the honeymoon. Come to think of it, the knock may also be caused by the fuel. I filled the tank with fresh 94 before I took it to him, but the car also sat for the winter with gas in it, may have gone a little bad. Maybe Ill run a few tanks through and then take it back and see if he can advance the timing a little more then.

Good luck with that, I think the only places that sell it around me are the Sunocco stations. There is a specialty fuel place close to me that sells all kinds of race fuel but its hella expensive. Id suggest finding some Sunocco stations on the route youre taking down to FL and make your stops accordingly.

[AaronGTR]

Originally Posted by Z3R0

I missed something i know, but what kind of SC did you use....M90?

He has one the limited number of magnacharger kits that were sold for the 99+ N-body. They used eaton M62 blowers. An M90 would have given more head room but they would have had to redesign the kit.



For gas, there are a lot of places in the U.S. that sell 93 octane. I can get it all over the place here in MI and it is usually 10 cents a gallon cheaper than the 94 octane from sunoco which is harder to find. I'd tune it on the safe side for 94 and it should work fine on 93. A few states you can only get 91 or 92 octane (ie california), but for the most part you can find 93.

[lastyear4gt]

OK, so I picked the car up tonight. There is wet snow tonight so I didn't get it much over 4psi of boost, but the car is very responsive and it is LOUD! The exhaust completely came alive and the charger wines like mad. I do have a bit of a stumble on medium throttle applications at low RPM, but I think that has something to do with the gap of the plugs. I know the tuner recommended NGK TR6's gapped to 40 thou.

I do however have a problem with a couple of the gauges. The oil pressure is only at 20PSI cold, and goes up slightly as it gets hotter, but does not vary at all with changes in tp. I am wondering now if it is not grounding well through the brass t I used to t off the the factory oil pressure switch and my guage sender.
What should the oil pressure be at roughly?

I also have a problem with the fuel pressure gauge, and I think that may have to do with the install of the sender. What I did was put a nitrous line to the end of the fuel rail and run it remotely over to the upper intake plenum just by the coil packs to the sender. But because the sender grounds through the threads, I soldered a small ground wire to the sender by the threads and put it under the mounting bolt for the sender's bracket. So I either have a bad ground, or the coil packs are inducing a voltage into the sender, but I cant see that being the case its more than 2" away from the coils.

So will the gauge ground itself through the NOS line or do I need that added ground I put it. On a sidenote, the gauge worked fine for the maybe 5 mins I had it running before I took it for tuning. I wanted to pop the hood and check the ground didn't come off again, as it has been a problem, but it was too cold, ill do it tomorrow.

Any suggestions regarding either problem would be greatly appreciated.

[bballr4567]

On my oil pressure gauge I vary from around 25-30 PSI at start up and when WOT at redline Im up around 60-63 PSI. Im using Mobil 1 synthetic but from everybody I have talked to they say that its pretty normal.

Id say that you either have a grounding issue or your wire is getting shorted somewhere. I didnt have the wire on the sending unit all the way when I first installed it and it only read like 10-20 PSI all the time.

[AaronGTR]

Hmmm... my oil pressure usually drops a little at idle after the engine warms up and the oil thins out. The gauge has never been really responsive, but the fluid pressure change would be more gradual than throttle input anyway, and it does go up when I give it a good amount of throttle. My fuel pressure gauge sender is a three wire and is self grounded so I didn't have to ground it. I'm pretty sure it would not ground well thru the fuel rail though. Don't know if where you have it grounded would cause problems or not, but it couldn't hurt to try running a longer ground wire to somewhere else.

[lastyear4gt]

well no, thats the problem. I soldered another ground wire onto the sender by the threads where it would normally ground and grounded it to the engine, thats what I dont understand.