ECR GM LS Daytona Prototype engines

[user-17438]

- Restrictor plate engine may require more development initially, as there is more extant knowledge about open engines. In the long run, though, the additional hp benefit from additional dollar invested will decline relatively quickly with a restrictor plate engine. The mass flow starts choking and stuffing more $100 bills into the engine will only do so much when the air flow is choking.

You may want to talk to some of the NASCAR guys.

The guy who sits next to me at Celtics used to own a team with his friends for a couple of years. I'll ask him! But in the mean while, can you explain where's the cost coming from? Is it just transitional cost when a different size plate is introduced? Or is there some reason why restrictor plate engine development is more expensive even in the long run with a constant plate diameter?

It is a lot of Engineering and testing on a daily to makea restrictor plate engine work. Just because you make the same power as the guy next to you doesn't mean it's not a turd at the track because you can't spin it rpm.. Back when I was involved, it was constant testing, track rental, engine dyno, chassis dyno. A lot wasn't even engine. It made the vehicle cost much more, I remember we tried Krytox for wheel bearings, Stuff was like $2000 for a 1lb.

Bottom line is the restrictor plate stuff made transmissions more expensive, rear end parts.. etc

Slowing people down just makes them try harder to go fast again.

Give them a specific valve spring to run, and valve weight.

[hoffman900]

Why wouldn't I do all that stuff with an open engine?

Again, it's expensive because you have to develop two different engine combinations. If the rules only spec one combination, then it doesn't cost anymore. You would still be doing the same development.

[user-17438]

Why wouldn't I do all that stuff with an open engine?

Again, it's expensive because you have to develop two different engine combinations. If the rules only spec one combination, then it doesn't cost anymore. You would still be doing the same development.

Different tracks, different rpm ranges.

[hoffman900]

Why wouldn't I do all that stuff with an open engine?

Again, it's expensive because you have to develop two different engine combinations. If the rules only spec one combination, then it doesn't cost anymore. You would still be doing the same development.

Different tracks, different rpm ranges.

Right, but that's not a restrictor adding more cost, that's just a function of the type of racing.

[DaveMcLain]

Why wouldn't I do all that stuff with an open engine?

Again, it's expensive because you have to develop two different engine combinations. If the rules only spec one combination, then it doesn't cost anymore. You would still be doing the same development.

Different tracks, different rpm ranges.

Right, but that's not a restrictor adding more cost, that's just a function of the type of racing.

I think what tends to happen is that when you restrict the field you slow everyone down BUT you also tend to compress the field and the difference between the best and the worst becomes much less. This means that it is now much harder to gain a significant advantage on the track.

[CamKing]

I think what tends to happen is that when you restrict the field you slow everyone down BUT you also tend to compress the field and the difference between the best and the worst becomes much less. This means that it is now much harder to gain a significant advantage on the track.

Yes, and if it costs you $10 million to run upfront, it costs you $9 million to make the field, and $20 million to win

[CamKing]

Why wouldn't I do all that stuff with an open engine?

Because you could gain more with a $500 camshaft, then $2,000 bearing grease.

Restrictor plates increase the cost to be competitive.
The last NASCAR restrictor plate deal I worked on, I designed 2 cams(4 new lobe profiles), and Comp Cams designed 6 new cams.
They dyno'd all 8 cams, and they were all within 3hp of each other. That's a lot of money to spend for 3hp, but because of the restrictor plate, 3hp could be the difference from 1st to 40th. Now think about the fact, that they have to do that same amount of development on every other part, that could help them or hurt them by 1/4 of 1hp.

[n2xlr8n]

Right, I forgot everyone over the age of 50 is a super genius. Man, just think if public education was what it use to be!

I'll ignore that

....but comment that it used to be an accomplishment to build a safe, high 8 street second car in your garage. Now, not so much.

Most of that can be attributed to technology, including the internet.

We used to be smart, though!


p.s. Love the GM prototype engine.

[Newold1]

Speaking of new GM engine offerings, how about this new piece of news and tech !!

www.lsxmag.com/news/lt7-cad-renderings- ... -turbo-gen vi-engine

Looks like GM Corvette is going into the DOHC twin turbo world ! I think this is an awesome development !

Damn, I can't get this web page address to load right, maybe someone more savy than me can!

[pamotorman]

they just announced the new 2019 1/2 ton chevy pick up will be available with a 6 cylinder diesel and 10 speed trans

[KnightEngines]

I flowed the heads I've got here last night, results were suprising.
A mate was there when I flowed them, we were betting on what they'd flow before they topped out, I said 360cfm, he said 350.
We were both wrong.

Flowed on a 4" bore, motor will be 4.07" bore, so I moved the head over a tad between flowing intake & exhaust to simulate the flow on a 4.07" bore.

Valves were 2.1/1.55" 7mm stem Delwest Ti.

Intake:
.1 - 56.5
.2 - 120
.3 - 185
.4 - 253.5
.45 - 282
.5 - 305
.55 - 316
.6 - 323
.65 - 333 - flow separation over the turn starting
.7 - 340
.75 - 338 - turbulent
.8 - 339
.85 - 337
.9 - 342

Exhaust
.1 - 49
.2 - 103
.3 - 149
.4 - 195
.45 - 205
.5 - 212
.55 - 215
.6 - 218
.65 - 219
.7 - 220
.75 - 222
.8 - 221
.85 - 220
.9 - 222

They are real strong from .3" - .6" lift, but after that flow separation occurs over the turn.
To isolate the problem to the turn I got out the 'magic ruler' - a 6" steel rule that's very handy, held in the port entrance near the floor at an angle up a little it holds the air down over the turn a bit.
Flow jumped to 360-370cfm & the port went quiet - so it's not valve/throat limited or port cross section limited, it can pass the air, just not nicely in it's current form.

So the peak of the turn needs some work.

My thinking is that GM designed these heads to make real strong mid lift knowing that port demand was going to be capped by capacity, camshaft & restrictor plate limitations - under those conditions the port would be real good.

But these are going on an unrestricted 6L engine, so I have to fix them Here I was thinking I was probably going to get away with just freshening them up.

Initially I'm thinking I just need to rework the peak of the turn a little, I'll probably hurt mid lift, but it has to happen, they need to be stable out to at least .8" lift.
On the exhaust side I'm going to step it up to a 1.6" valve, the 1.55" is pretty much tapped out in throat size, the ex port is admirable given the valve size, but not up to the task of a 6L unrestricted engine, it's choked on the throat, to get more throat I need more valve.

[CarterHendricks]

Speaking of new GM engine offerings, how about this new piece of news and tech !!

www.lsxmag.com/news/lt7-cad-renderings- ... -turbo-gen vi-engine

Damn, I can't get this web page address to load right, maybe someone more savy than me can!

http://www.lsxmag.com/news/lt7-cad-rend ... -vi-engine

--Carter

[Newold1]

Thanks Carter.

Quite a technology leap for GM in performance engines. The future marches on with some of us still "kicking and screaming" !

[Warp Speed]

I flowed the heads I've got here last night, results were suprising.
A mate was there when I flowed them, we were betting on what they'd flow before they topped out, I said 360cfm, he said 350.
We were both wrong.

Flowed on a 4" bore, motor will be 4.07" bore, so I moved the head over a tad between flowing intake & exhaust to simulate the flow on a 4.07" bore.

Valves were 2.1/1.55" 7mm stem Delwest Ti.

Intake:
.1 - 56.5
.2 - 120
.3 - 185
.4 - 253.5
.45 - 282
.5 - 305
.55 - 316
.6 - 323
.65 - 333 - flow separation over the turn starting
.7 - 340
.75 - 338 - turbulent
.8 - 339
.85 - 337
.9 - 342

Exhaust
.1 - 49
.2 - 103
.3 - 149
.4 - 195
.45 - 205
.5 - 212
.55 - 215
.6 - 218
.65 - 219
.7 - 220
.75 - 222
.8 - 221
.85 - 220
.9 - 222

They are real strong from .3" - .6" lift, but after that flow separation occurs over the turn.
To isolate the problem to the turn I got out the 'magic ruler' - a 6" steel rule that's very handy, held in the port entrance near the floor at an angle up a little it holds the air down over the turn a bit.
Flow jumped to 360-370cfm & the port went quiet - so it's not valve/throat limited or port cross section limited, it can pass the air, just not nicely in it's current form.

So the peak of the turn needs some work.

My thinking is that GM designed these heads to make real strong mid lift knowing that port demand was going to be capped by capacity, camshaft & restrictor plate limitations - under those conditions the port would be real good.

But these are going on an unrestricted 6L engine, so I have to fix them Here I was thinking I was probably going to get away with just freshening them up.

Initially I'm thinking I just need to rework the peak of the turn a little, I'll probably hurt mid lift, but it has to happen, they need to be stable out to at least .8" lift.
On the exhaust side I'm going to step it up to a 1.6" valve, the 1.55" is pretty much tapped out in throat size, the ex port is admirable given the valve size, but not up to the task of a 6L unrestricted engine, it's choked on the throat, to get more throat I need more valve.

What is the current exhaust throat and seat angle?

[hoffman900]

Tony, I might have missed it, but were these heads already ported or just as-cast?