285 whp!

[RallyBob]

Originally Posted by sicksubie

what valve springs do you have on the motor again?

They are the Supertech WRX spring/valves/retainers. These are taller than the SVX parts, but fit perfectly with the mechanical bucket conversion.

[TomsSVX]

I was always under the impression that the wrx valves were of equal diameter??

Tom

[RallyBob]

Originally Posted by TomsSVX

I was always under the impression that the wrx valves were of equal diameter??

Tom

Yes, but Supertech offers a .5 mm oversize head diameter as a no-cost option.

I originally wanted +1 mm intake and +2 mm exhaust, but that would have added quite a bit more to the overall costs.

Bob

[TomsSVX]

I am sure... Not to mention stuffing those valves in would have been a trip. What did you use for vlave seats in this project or did you simple cut the stock ones??

Tom

[RallyBob]

Originally Posted by TomsSVX

I am sure... Not to mention stuffing those valves in would have been a trip. What did you use for valve seats in this project or did you simple cut the stock ones??

Tom

We just had the stock ones cut. Going with the bigger valves I originally wanted would have meant bigger seats...again more cost!

As it is, I unshrouded the chambers for better exhaust flow. I suspect with the + 2mm valves I'd have been looking for a bigger bore area too to facilitate better breathing.

Bob

[TomsSVX]

great info Bob, it will come in handy for future head build ups

Tom

[RallyBob]

Originally Posted by TomsSVX

great info Bob, it will come in handy for future head build ups

Tom

No problem, glad to help out.

On another note, I have dug out my old video camera, and purchased a new battery for it. I intend to do a mini-documentary of Jack's car...a thorough once-over showing the overall build. Let's keep in mind this is Jack's personal car and not a 'shop' car, it was built within serious budget contraints. I'd also like to get some live-action footage at VIR this weekend.

Since my camera is an 8 mm and not digital-recording quality, and I have severely limited computer knowledge (hey, I'm in my '40's and back in high school I didn't even know what a computer was), I was going to ask you if you are capable of converting it to a digital format so that it can be seen and heard live-action. If so, I'll send you the tape when I'm done so you can make it available for those who want to see it in action.

Bob

[SVXRide]

Originally Posted by RallyBob

No problem, glad to help out.

On another note, I have dug out my old video camera, and purchased a new battery for it. I intend to do a mini-documentary of Jack's car...a thorough once-over showing the overall build. Let's keep in mind this is Jack's personal car and not a 'shop' car, it was built within serious budget contraints. I'd also like to get some live-action footage at VIR this weekend.

Since my camera is an 8 mm and not digital-recording quality, and I have severely limited computer knowledge (hey, I'm in my '40's and back in high school I didn't even know what a computer was), I was going to ask you if you are capable of converting it to a digital format so that it can be seen and heard live-action. If so, I'll send you the tape when I'm done so you can make it available for those who want to see it in action.

Bob

and there's a problem with someone being in their 40s?
I can do the conversion to digital if YT doesn't have the necessary hardware, as our family camera is a Sony Hi8 that also doesn't have digital output (thus requiring me to buy a box that Sony conveniently offers to convert the output to digital)
-Bill

[Tim]

The VRD MC3 by sony is a pretty cool little device. The studio I do work for has the equipment for converting hi8 to digital. I also found out about the o scope. its roughly about 10 to 15 years old so im not sure if its going to be any use to you.

[longassname]

Many old oscilloscopes are very good. I didn't catch what exactly you need an oscilloscope for but I would expect most any 10-15 year old oscilloscope to have the bandwidth necessary whatever you might be doing on an SVX. The quality of the probe used and it's calibration are far more important than the age of the oscilloscope. My TEK unit isn't that old but it's no brand new multi-gigahertz unit either. The problem you will find is nobody will want to ship or haul around their oscilloscope because that's when they break.

Originally Posted by TE1221

The VRD MC3 by sony is a pretty cool little device. The studio I do work for has the equipment for converting hi8 to digital. I also found out about the o scope. its roughly about 10 to 15 years old so im not sure if its going to be any use to you.

[RallyBob]

VIR has come and gone. The bad news is that I never ended up making it down, so I have no photos or video to share. The Impreza also suffered some overheating issues. Basically the engine was not designed to be run continuously at high rpms.

The problem has shown itself previously, even running at 6500 rpms. About 15 minutes into any racing session the oil temp gets very hot, then the coolant temps quickly follow. When the temps get high enough, the radiator cap blows off some pressure, discharging coolant into the overflow and then an air pocket is created, and the temps start to climb like crazy. The only option is to slow down and let everything cool, then after the race top up the coolant and purge the system of any air. The car then runs fine through the next race session, again 15-20 minutes in.

The car runs an aftermarket oil cooler, as well as an electric coolant pump. This has extended the useable range in general, but the addition of another 1500-1700 rpms has brought the problem back. The next step seems to be a custom oil pan with trap doors, baffles, and perhaps a crank scraper. Oil vapor is being drawn into the intake plenum under deceleration, pointing towards a windage problem at the higher rpms being seen.

The good news however, was two-fold. A new power steering pump and reservoir was tested. The old SVX pump would get so hot, it would singe your flesh to touch the metal reservoir after any track events. It would often also expunge the contents onto the top of the engine, and the power steering would start to lose effectiveness. This was with a remote cooler added! The aftermarket KRC pump and alloy reservoir worked excellently, the power steering worked fine (even with a 2:1 steering quickener), it didn't puke any fluid, and the reservoir remained cool.

The other good news is that the car was faster than ever. Almost 10 seconds per lap faster than the last time the car was run at VIR. It's running in the 2:14's on the long course. This was with the addition of the added HP, but also partial credit goes to some revised spring rates just installed. Prior to overheating, the car had enough outright speed (and light weight) to pull on a stock-weight 360 whp EVO IX in top gear. And it was nearly an equal match for a C5 ZO6 Corvette. The Impreza pulled the 'vette out of the turns and only at the top end of 5th gear would the ZO6 start to close in 3-5 car lengths.

Ultimately though, 5th gear on the 5MT shedded itself, so the car had to drop out as running 4th only is not an option at VIR. Speeds approaching 152 mph were seen prior to the 5th gear departing.

More news as it develops.

Bob

[TomsSVX]

Sounds impressive... Only question/concern... Are you sure it is the fact that the engine runs so hot or that the new found HP is stretching the head bolts too far causing compression to leak at high HP levels?? The fact that the oil gets that hot leads me to believe what you have said it true but still something to think about. What are you using for head bolt/studs and also what gaskets are you using??

Tom

[longassname]

You may want to shoot boxersix a pm. I think he said he is already working on a dry sump system. I understand he has a VMC big enough to do the pan. I have a large VMC and may pop one out myself but it won't be in time to help you.

I'm guessing you didn't use any thermal coatings?

[RallyBob]

Originally Posted by TomsSVX

Sounds impressive... Only question/concern... Are you sure it is the fact that the engine runs so hot or that the new found HP is stretching the head bolts too far causing compression to leak at high HP levels?? The fact that the oil gets that hot leads me to believe what you have said it true but still something to think about. What are you using for head bolt/studs and also what gaskets are you using??

Tom

Stock head bolts. Not sure on the head gaskets to be honest. But I think they are OEM Subaru. It always ran hot, even when it was bone-stock. Not initially, only after 15-20 minutes on the track, once things got 'cooking'. Getting in racing traffic doesn't help, the cars in front block airflow to the radiator and oil cooler. We've never found coolant in the oil either.

When the old heads came off, there were no signs of leakage, FWIW. And the plugs got pulled at the track, they were very clean. It's not uncommon on a lot of engines (SR20 Nissans are very prone to the same issue for example) to exhibit high temps only under sustained duress. An autocross or drag strip run will never show it in other words, not enough time spent at elevated rpms and loads.

I want to do something with the oil pan, the entire 'soup bowl' design always bothered me, because at those G-force levels I know the oil is climbing up the walls of the oil pan and becoming aerated by the crank....8200 rpms and 1.2+ G's was probably not within the original design constraints!

Bob

[RallyBob]

Originally Posted by longassname

You may want to shoot boxersix a pm. I think he said he is already working on a dry sump system. I understand he has a VMC big enough to do the pan. I have a large VMC and may pop one out myself but it won't be in time to help you.

I'm guessing you didn't use any thermal coatings?

Stock shortblock, it's never even been taken apart!

So, no coatings to anything...not the head, valves or pistons.

I'd love to see a dry sump on this car, but knowing Jack's budget, it won't happen. Engine development can be fun, but only when someone else is paying for it.

Bob