Let's assume...bench racing a claimer motor.

[SpiderGearsMan]

6.2 comes in half tons - aluminum block - 426 hp in camaro and GXP G8

[dieselgeek]

It maybe like Stock cars when we raced Dirt, there was a 850.00 Claim, and we ran a 15,000 engine...... the same as everyone else.

Hunkins was talking about *requiring* the top three finishers give up their engine for $4000. APparently it's not very popular to claim an engine in any of the existing claimer-ruled racing classes (the roundy round guys).

[SpiderGearsMan]

yep , IMCA is big on claimer engines

[TheSilverBuick]

That would be bitchen, then they could put them in appropriate magazine cars!

[38P]

You seem to know a lot about the Mark VIII motor. How would you go about building one that makes BIG torque down low, and shifts the powerband down to a peak before 6500rpm? These motors aren't typically torque monsters (until you put compressed air into them, then wow!!) but it would be kickass to show up with one that was at least a player.

That's one of the reasons I like the twin-port B heads (other than dirt-cheap cost) . . . you've got two smaller ports to play with . . . . The mill's going to respond to intake runners, increased compression, cam timing, and port velocity . . . .

[38P]

I think the variable valve timing will help the low rev torque plenty when you are dividing by cubic inches.

2x But (1) is it legal in EMC? And (2) can you get any decent cams that work with it?

[38P]

Nobody has run with a VVT set up yet. I can certainly say that it does a bunch to flatten the torque curve on the Ford engines that I've looked at.

Does GM have a VVT V8? In an LSx configuration, I'm not going to try to work with a Northstar or one of the other expensive orphan, no aftermarket support, engines.

Single cam VVT, unless you have a cam-in-a-cam, like the last Viper 'plant, leaves a lot to be desired. The real attractiveness of TiVCT is the ability to independently vary the exhaust and intake timing. Of course, one step better is V-TEC, which has a two-step lift added, but that's not on the current EMC menu.

[kyhunter89]

2x But (1) is it legal in EMC? And (2) can you get any decent cams that work with it?

1. no clue
2. not yet. Lifters are the problem people are reporting if I remember correctly, but that might not be a problem at lower (6500) rpm.

[38P]

Nice job!! Your comments about bore size and piston speed are an important part of the excercise. The biggest bore is not always the best way to go in this competition.

Small bores are going to be more detonation resistant on octane-limited fuel because lateral chamber distances are reduced. The tradeoff is that small bores really hurt two-valve breathing (not so much a factor when four valves are in play)

[38P]

Jag/Lincoln AJV8, mainly just to be different but like the Mod Motor guys, need to allow DOHC to make it compete.

They'll probably set the minimum cubic inch limit too high for this mill to be eligible (assumption based on the current minimum CID rules)

[38P]

Lifters are the problem people are reporting if I remember correctly, but that might not be a problem at lower (6500) rpm.

Hmm? I didn't know that. I thought the main problem was piston/valve interference . . . at least one cam company was selling a VVT restrictor or lock-out so that they could peddle longer-duration profiles.

There is a lifter problem with the DOD lifters not working with higher-lift cams . . . But DOD isn't going to be a factor in EMC competition.

[dieselgeek]

We looked into the late LS version of VVT, and were told that these systems don't work well with any kind of increased valvespring pressure.

[38P]

Is the RPO L92 VVT system hydraulic?

[SuperBuickGuy]

Is the RPO L92 VVT system hydraulic?

yes

[38P]

Thanks!

Then I assume that if you wanted to run stiffer valvesprings, you'd have to figure out a way to bump up the line pressure to the VVT actuator to compensate for the extra torque loading on the camshaft. Not easy to do with a single-stage main-gallery mounted internal oil pump. Or you'd have to modify the VVT actuator to impart more torque to the cam when it rotates.