Dave, I would be curious as to the lopeyness of those cams on a stock/flashed ECU vs. the AEM with the idle compensation.

Think customers would be able to live with them + stock ECU?

Also I heard the stock retainers bump the valve stem seals prematurely wearing them out. Would you assume that it would make the contact much worse with the 280's? It seems there are aftermarket "low profile" retainers that solve the problem. Would the same low profile retainers still clear the stems on the 280's. -Thanks Dave.

 

The lift is the problem with the contact not the duration. 264's/272's have the same lift so I would bet the 280's have the same as well.

There is another thread that answers this question a couple times.

Terry S

 

yep they have the same lift as the others....as far as i remember

 

Lift is the same, duration is changed. We took some measurements today at the machine shop in reference to the other thread about the contact problem. There isn't a problem.

These 280 lift cams are LOPEY LOPEY LOPEY. I am sure someone will put them in a flashed, afc or stock EVO sooner or later but to be honest I cannot imagine the idle being that great.

There is an absolute horsepower increase. Right out of the box and into the car it picked up 15 whp or there about.

The turbo in this car is just flat out done and out of wind. It will NOT maintain any high boost levels at all. We tried three different boost controllers, no change. We even tightened the wastegate actuator all the way down today to try and maintain more boost at redline and have less of a spike. No matter what nothing works, it is just under turbo'd now.

Once again the car spiked way over 400 whp on the tire spin and boost spikes I was getting but would settle down.

The last two runs I tightened the straps as tight as I could (believe me, that's tight) and dropped the boost to what I think is "reasonable". The boost would spike to 24 psi and then by redline it was down to 18 psi. If I could tune this car with a turbo that would keep up and just run a steady 20 psi the power would be unbelievable.

So here is what has happened the last few days:

Added the ported/coated exhuast components to the car 361 whp (341 at redline) 367 ft lbs

Added the clipped stock turbo to the car 358 whp (341 at redline) 361 ft lbs

Added the 280 degree HKS cams to the car 382.4 whp (358 at redline) 368 ft lbs.

The cams themselves did not allow this huge gain in power. As I said just dropping them in gained about 15 whp. The extra came from some additional tuning. The car needed more fuel with these cams from about 3600 rpm up to redline and then I was also able to add another 1-2 degrees of timing throughout the entire curve. Total HP gained was 24.4 and only 7 ft lbs of torque.

It's been a good week. 300+ dyno runs on the RS. NO signs of any head gasket pushing water, no plugs burnt off nothing. I don't want to blow my own horn but I am very proud of fact that I have been able to make this much power on a honest 94 octane fuel.

We are talking about a stock appearing EVO here laying down 382 whp on 94 octane fuel. That is mid-11's with a good driver in the car.

David Buschur
www.buschurracing.com

 

Nice work Dave. We all appreciate it. I think I'll stick with the 264's as I don't want to be stalling in the stop and go traffic.

 

Would it be possible to test straight 264s and overlay all the runs of stock vs. 264 vs. 272 vs. 280 on one graph?

That way it would be easier to see the power curve of running the various cams.

 

that will be nice

 

Before putting the 20G on, you might want to get the car into a more traditional state of modification. Very few are going to run 280/280 cams or a clipped stock turbo (especially after your lukewarm review). What would be optimal is bolting the 20G onto a car with only your Stage 4 mods.

 

Very true... maybe even a stage 3 as you KNOW people are going to do it.

 

Id like to know why the car lost HP with the sheetmetal and the extrude honed manifold with the throttlebody. The velocity of the incoming air dropped dramatically? I have never seen a dyno of a sheetmetal actually lose hp.... maybe on the bottom end but even still not much. Whats the deal with that?

 

Damn I am totally engrossed in this thread. I'm a 45 year old engineer designing custom severe service control valves for the petro chemical industry and am more than a little familiar with developmental testing. Dave you have my utmost respect for the courage and integrity to be so brutally honest with your approach and results. Your enthusiasm is infectious. You are a true gear head and I don't give better compliments than that. I wish you were down the road so I could donate my free time to turn wrenches for you. For those of you who've never done this kind of work you can't imagine the value of the information dave is posting here.

 

Phenomenal effort isn't it...

 

My initial intentions were to test the 264 cams, then 272's, then a combination of them and then finally the 280's. What ended up happening was I had no 264's so I put the 272's in and was so impressed with the power that I just continued on adding and tested other parts that needed to be tested.

I got so geeked about the car making power I wanted to coninue making more. HKS has been on my butt a little bit about testing these 280's as we got the first 2 sets available shipped to us a few months ago. They sat on my workbench. I got a call that we needed to make up our mind whether or not they worked and place the remainder of our order. I bought an additional 10 cams without knowing if they would work.

As you guys can tell, I am FREAKING CAR NUT, I get as wrapped up in this stuff as you guys do. Making less power isn't usually on my adjenda. I guess I was in no hurry to make less and go back to the 264's.

At this point I will have to be honest and say I probably will not be going back down in cam size for testing. It could happen and if it does I will only test the 264's together and no combination of the any. (i.e. 264/272)

I believe the best choice for the car is going to be the 264/272's just as it was in the old DSM's as that is what we found back then to be the best all around combination. The idle and driveability is fine like this with the added power of the 272 exhaust cam.

When the 20g goes on the car it will be tested with the 280 cams that are in it right now. The turbo that is on its way to the shop is a titanium/aluminied 20G in the 10.5 housing. We are hoping by using that combination that the spool up will stay very close to stock.

Maybe if you guys stay on my butt about it (not too much though once I get the turbo one the car and test it I can then drop the cams down to the 264's and test again. This would give me atleast an idea of the difference in power from 264 to 280's and we can kind of back figure from there.

The clipping of the turbine was definetely marginal at best. Something that I am not going to push to anyone. The decreased backpressure in the turbine housing did allow more timing to be added but in the end the power was still down overall. I was surprised as that is not what I expected. There has been alot of testing done that I didn't see what I expected........which brings me to the intake manifold.

I don't honestly know what the deal is with the intake manifold testing. I put more work into trying to make the extrude honed intake and sheetmetal intake make more power than I did to any other part. Most, if not all, of the other parts tested were an instant realization of power or you could atleast look at the datalog and see if something needed to be changed to make the power. For example, put on a new part see the boost drop 3 pounds, simple, turn it back up and test again. See the AFR's go real lean, add some fuel and test again. With the intakes I couldn't really see what was going on. The boost did drop with them but no matter what I tried I could not get it back. Up until I added both intakes I was able to hold 19-20 psi at redline. After I have had less and less boost. There are no leaks, no blow by, no headgasket issues. I believe the airflow was increased with both intakes and the turbo has just become "smaller" and "smaller" as the efficiency of the engine has increased.

Right now I have the wastegate actuator arm as tight as it can go. With just a straight hose running from the intake to the actuator it will put out about 15 psi of boost. Like this the car STILL made just short of 350 whp at redline. This was amazing to me. I think I saved the dyno sheet, it would be an interesting one for you guys to look at. Remind me I will post it here. Amazing what a boost control does to low end power.

Hammerr,
Thank you. Probably one of the coolest posts I have had someone direct towards me. You should see my home garage if you think this stuff makes me a gearhead! haha Today I put my '71 Chevy Truck back together......then on to the '56 Bel Air.......then.....it's a disease.

Thanks for reading guys,

David Buschur
www.buschurracing.com

 

But a good disease! Thanks for all the hard work and "Truth till it hurts info". As I re-read this post I'm so thankful I choose the right "HP Merchant" at the start of my EVO Track-day project. Thanks again Dave and the rest of the Crew at Buschur Racing!

 

Hey David,


What was that tracking # they gave you from FEDEX or UPS for the new 20G ??????? (Gonna Hijack The Truck) J/K.


I'm very anxious to see what happens with this new turbo, can't wait to get one.


My fingers are crossed for you. Goodluck and thanks for keeping us posted.


Derek