Hanks URQ 2.6L Autopsy

[gtn116]

Those FSAE cars are pretty slick. I almost got in as fuel management as a freshman because of my researching, but the seniors were a-holes and basically forced me out and they didn't meet the deadline for registration. I was really hoping to be able to do it. This year they're also doing a turbo single-cyl setup, I believe. honda 400ish.

[loxxrider]

I like the goals Hank... I see the same for myself... big sucker for when I want it and "small" turbo for the track.

[Lord_Verminaard]

Damn, you are not screwing around. T'would make the boys at Audi's motorsports division pretty proud.

Can't wait to hear this thing fire up with the new guts. Keep it up!

Brendan

[Marc]

My work for battleborn must be done by the 28th of August. I start my last real semester of college that includes 6am-11am every morning working on the Forumula SAE car. I am working with the drivetrain portion of hte build, which will include a yzf 250cc 4 stroke motor. Naturally, I will slap a turbo on. In motorcycle engines, you have a jug that splits from the case. I plan on putting an 8mm spacer in between the jug and the case along with double gaskets in order to make a "tall deck" configuration. I'll run a custom rod along with a custom piston and rev it to around 17k! The same motor made 28whp last year on our dyno, and this year I hope to triple it to a healthy 85whp!!

I don't know how much time I will have with the car. I hope to have the stroker in with a balanced assembly and a serpentine setup before BBQ. I'll likely run the same 3582r till the springtime and use just a basic ferrea valved head with 7a cams. This last winter was it's last snow winter. It is only mild rain from here on out for the old horse. This spring I will probably put in Cats with solid lifters and a gtx42r and shoot for 1000whp on the setup.

they make you run restrictors on the 250's? They do on the 600's I've helped with over the last few years. The trick is to push the torque curve as early as possible and hold it flat to redline. Once you hit choke flow, thats all she wrote...

[Hank]

Yes, they do require a restrictor, but it can be post turbo. That helps A LOT! The restrictor for us is set at 13mm. This is Forumula Hybrid btw, and the rules are a little different. Last year, we had 600WTQ with electric motors, but the thing weighed almost 600lbs. Off electric, the thing was a slug. If we can get reasonable power out of the gas and shave 200lbs off the car in battery and motor, we should be more competitive with 70whp and 300wtq worth of electric

[my2000apb]

ok enough of this SAE stuff, put it in a thread becasue we want to know a lot more!!

[Hank]

Well, I found something this evening that I am happy about. You see, after the the 612whp dyno day, I lost a bit of compression in 2 cylinders. It was not a lot, but I was only seeing 130psi in those two cylinders where I was seeing 155psi in the other 3, the same as when I put the motor together....

Well, today I brought I finally took the pistons off the rods so I could bring an AAN piston home to weigh it against my new stroker pistons. I was weighing them and looking at the spacing of the ring lands on the OEM pistons vs the JE unit. that is when I noticed this small little crack. I smiled when I saw it as I knew I would see another crack on the other side of the piston... Sure enough, the ringland busted.

This motor never saw a lick of detonation. The bores were uber clean(well the ones that did not see a valve bouncing around) and I have to believe that this is the limit of the AAN piston for day in and day out abuse. Anyway, here are the pictures of the carnage. I can't wait to get to the shop in the morning to see if I have a #4 broken ringland as well!!!! It makes me feel slightly better about the whole situation really.









Anyway, New piston package is about 110 grams lighter per piston than the AAN pistons despite being 2mm larger bores, heavy duty wrist pins and 21mm pins vs 20mm pins. That is 550 grams lighter than the AAN pistons. That is almost a pound and a half worth or reciprocating weight. While the 95.5mm crank is about 5.5lbs heavier than the 86.4 crank, The original pistons that came with the 95.5 crank are almost 220grams heavier than the new JEs. Hopefully I can take the same 1.1kg out of the crank counter balance to end up with a crank that is only a couple of pounds heavier than the AAN, coupled with a lighter reciprocating mass and an identical rod ratio of 1.66. Yum

I posted this one already in a different thread, but I shamelessly post pictures of my boy whenever I can.

[PRA4WX]

That is absolutely shameless! ;-p
You aren't considering lightening the crank are you?

[loxxrider]

Ha, thats an awesome pic of the boy.

Glad you found the practical limits of the AAN piston. Makes me not have to now lol.

Your scale is really ghey.

[Lord_Verminaard]

Wonder if thermal coatings on the oem pistons would raise that limit any? Either way, that is pretty respectable.

Some vw 4-cylinder people have lightened the crank by a good amount with no after-effects. Just taking enough weight off to take in to account the weight loss from the pistons (and rods maybe??) is not going to weaken it enough to worry about it, I would think.

Put the kid to work and get this built!

Brendan

[123quattro]

Hank,

Good that you figured out where that compression went. However, I would disagree that your engine didn't see any detonation. Ring lands on our pistons are ridiculously overbuilt. I don't see normal combustion pressure breaking those, ever.

Anyway, the new pieces are pimpy.

[Hank]

I agree that our pistons are overbuilt, but being "forged" does not tell the whole story. 80's forgings are no where near as sophisticated as today's forgings. 350hp/liter is a bit to ask from any piston.

This motor never saw anything but e85. All pulls on the dyno were done with knock phones on with me personally listening to activity. If it did detonate, I didn't hear it. I can post up the soundbit from the dyno as well, as i think I still have them on the computer. I am 99% confident that his motor did not see any detonation events, especially on the dyno where compression was lost. I ran compression 30 minutes before the dyno and as soon as I got home from the dyno.

It is hard to get e85 to detonate. It may not crater pistons like gasoline do, but it still sounds like a dull thud on phones. I heard it on my old wiseco motor through the phones, but never on this AAN bottom end. The logical alternative to shear power is perhaps ring gaps on the low end of what 350hp/liter would need. If a ring did close off from crazy high cylinder pressures due to shear power( I hear detonation creates ~5500psi peaks, where a 350hp/liter motor can produce around 4000psi for reference), it would have the pressure behind it to chip off a ring land like it did. The at is the ring land that would be the first to go. There is no way in hell the main crown would go.

[TheArchitect]

Det frequently causes ring lands to crack and break, its near impossible to hear during a dyno test.
To even stand a chance of hearing det under those circumstances, you usually need det cans.
A remote mounted stethoscope could make a huge difference.

[Hank]

Yes, I listening to the knock sensor through a amplifier and headphones while on the dyno. While it takes some study of the frequencies associated with detonation, once you hear it, even a trace is like hearing English over static.

I got to the shop to find the other cylinder had the same failure. The oyher reason I doubt detonation is that this is the exact same tune with 3 Lai less boost for over 10k miles and literally a thousand pulls to redline. Full track days in summer exc. If it was detonating enough to crush a ring land 1000 pulls ago, it would have done more damage than a ringland. The pistons show zero sign of detonation. Also, we have the dyno charts of the pulls... Smooth power and detonation do not go in the same sentence.

Maybe I am up in the night. Anybody know of another AAN piston making 800 crank? Perhaps they had different results...

I really doubt these pistons were cold forged as well, as hardly anything was done that way in the 80s when this forging was designed. Hell, hardly anything Oem is cold forged today. Forging a piston at 950 degrees is different than the 450F in high end stuff. Better than cast? Sure.

[bimmerboy]

What CR are the new slugs? Dish is obviously much bigger than the AAN but can't tell if that's just to make up for the extra displacement.

[Hank]

Yes because cr is total displacement divided by volume at tdc, 516cc now displaces one cylinder where 445cc was there before. Therefore more dish is needed to achieve the same cr. They are designed as 9:1 and I will run them initially with a decked head to get up to the same 9.7:1 I had before for baseline, and then I will build a monster head over the winter and bring it back to 9:1 they would he with a virgin head.

[Wizard-of-OD]

Some vw 4-cylinder people have lightened the crank by a good amount with no after-effects..

If N/A sure but forced induced is a different department.

[Quattro v1.0]

Great info, bust just too much bench-racing. Hank go build this thing ;o}

[Audilard]

That really is impressive how much power and abuse the stock pistons can take. Reminds of the movie U571 when the guy says at 200 meters deep...."those Germans sure know how to build a boat"...same goes for engines.

[Hank]

Back in business!!!

[psychorallyfreak]

[RSCoupe]

:woowoo:

[nsimps]

Some say a picture says a thousand words. I say this picture says more, much much more.

[Hapster]

Back in business!!!

Well that's a cute lil turbo Hank ;>)

Hap, with some kind of funny near Everboost, Maguire

[Audilard]

Does that turbo have internal pistons, fuel injectors, and some plugs??? I don't see a 2.6L long block anywhere!!!