How To Lower Intake Temps Without Alky

[SloGN]

a year or so back, i posted a question about building a 4.1 for my 84 T Type with about 10:1 compression that used the later heads like the ones used on the TTA with a reverse dome piston that mirrors the chamber shape to be run on E85.. the general consensus was that i was crazy for wanting to try such a crazy thing. a few people didn't know what a reverse dome piston was, but there was a discussion about them and what quench is and that kind of thing.

so maybe i wasn't crazy?

nah

if you use the TTA heads i beleave the combustion chambers are smaller than the 8445 heads. so you may actually get more than 10.1 . You can build it and it will fly!

 

[novaderrik]

nah

if you use the TTA heads i beleave the combustion chambers are smaller than the 8445 heads. so you may actually get more than 10.1 . You can build it and it will fly!

the reverse dome pistons would have to be custom made, so the desired compression ratio could be dialed in that way. i think there is a company that has the specs for a a reverse dome piston for the 4.1 because someone on here had them spec'd out, but i can't remember who it is.. Mahle, maybe?

i figure 10:1 would be a good comprimise compression ratio that would allow the car to be a beast off boost and still allow a decent amount of boost to build power.. it would also be low enough to allow a guy to limp the car around with pump gas if E85 isn't available..

 

[SloGN]

the reverse dome pistons would have to be custom made, so the desired compression ratio could be dialed in that way. i think there is a company that has the specs for a a reverse dome piston for the 4.1 because someone on here had them spec'd out, but i can't remember who it is.. Mahle, maybe?

i figure 10:1 would be a good comprimise compression ratio that would allow the car to be a beast off boost and still allow a decent amount of boost to build power.. it would also be low enough to allow a guy to limp the car around with pump gas if E85 isn't available..

If it were me doing that kinda build i would take and use a set of alum heads for the better port flow and chambers. My current engine is almost 9:1 and it runs 97-98 mph in the 1/8 with only 15-16 psi of boost. so using 10:1 could make up for having a hot-air set-up. just a thought.

 

[novaderrik]

If it were me doing that kinda build i would take and use a set of alum heads for the better port flow and chambers. My current engine is almost 9:1 and it runs 97-98 mph in the 1/8 with only 15-16 psi of boost. so using 10:1 could make up for having a hot-air set-up. just a thought.

i'm a broke ass junkyard scrounger.. you don't generally find aluminum heads for a Buick V6 in the junkyard, but you can't turn around without almost knocking a window out of fwd Oldsmobiles and Buicks..

 

[Jerryl]

Copied from another thread . . .

Re:Cold Air Kit

. . . . . . . HA create enough charge heat and don’t need anymore of it even at lower speeds. Calculated RWHP impact from 130 to 70F is about 25 WHP . . . well worth it.
Intake restriction also has a big impact on the efficiency.

Calculated;
For every 1” Vacuum pressure drop in inlet restriction, the charge temps increases 10F!
For every 1 lb boost, charge temp increases 11F.
For every 10F temp drop of compressor intake temps, WHP increases 3-4 HP . . . . all else being equal.
For every 11 deg decrease in charge temps, WHP increases 4-5

Think about the variables you have the ability to control and the associated compounding effect . . . . .


This is for Charlie . . .
“If” you had intake air temps of 130 and sprayed alky . . . and temp dropped to 90, you should expect a 13-15 hp increase.

 

[bison]

There's more to it than just looking at the charge air temp. I've had old wheel designs flat out stall and charge air temps were still right in line. The t66 seems to die at around 75lbs/min regardless of the intercooler, amount of meth, size of the engine or engine speed. It simply can't keep up. The drive pressure is too high. What this means is that even if all the ex pressure which in my examples was very high is sent through the volute with zero bypass it's still not enough to get a higher shaft speed. This can be caused by things such as the compressor wheel itself, inlet restriction, or compressor housing design. Or a combination of them. I ran the 62cea to 78lbs/min on the same engine. It occurred at 28-29psi on the same engine at sea level. Both on the same day. With the 62 the drive pressure was not the limiting factor. It had no problem making more boost. I actually had it as high as 33psi but flow dropped to 74-75lbs/min. Charge air temps jumped about 60*. The pipe between the turbo and intercooler was so hot water would boil if i sprayed it. This was measuring the temp post intercooler and after spraying as much as Razors kit flows. Still saw 125-130*! One way that could have further increased the engines mass efficiency would have been to increase the CR to take full advantage of the compressors limitations. With the t66 it would have taken almost 11:1 and the 6265 around 10.5:1. This would be running at least 116 octane. The cam intake and ex duration could have been slightly reduced and a tiny bit less LS ground into the cam. All of which would help the engine move more mass flow with the same PR's I used. Exhaust pressure may actually increase under those conditions so the t66 might have made a tiny bit more boost and ran more effectively since it wasnt making heat yet. On a 9.3:1 engine the t66 made 687whp with more timing than I ran on the 9:1 engine but cams weren't the same so it's not a total comparison and mass flow was likely still around 75-76lbs/min.

 

[b4black]

How about open valve vs. closed valve injection? The new direct injection engines spray directly into the cylinder - the heat is absorbed from the air, not the intake manifold or backside of the intake valve. Using a larger fuel injector to spray the same amount of fuel, closer to and after the valve opens will mimic DI. Use a larger injector with a 40% duty cycle vs. a smaller injctor with a 80% cycle.

 

[Jerryl]

............The pipe between the turbo and intercooler was so hot water would boil if i sprayed it. This was measuring the temp post intercooler and after spraying as much as Razors kit flows. Still saw 125-130*! . . . . . . .

Most HA cars would be happy with 130F.

How about open valve vs. closed valve injection? . . . . . .

I discussed this exact strategy with TT about two years or so ago . . . program an offset in the injectors . . based on the cam timing.
I was not ready for it (Still not ready to design that experiment ) . . . and don't remember the outcome of the discussion . . . but if anyone can do it, TT can!

 

[bison]

Most HA cars would be happy with 130F.


I discussed this exact strategy with TT about two years or so ago . . . program an offset in the injectors . . based on the cam timing.
I was not ready for it (Still not ready to design that experiment ) . . . and don't remember the outcome of the discussion . . . but if anyone can do it, TT can!

Yeah but that was with baselines in the 65-70* range. 60* increase equals about 6% power loss. You could easily run the same 62cea compressor on a hot air and pretty much not ever run it out of breath. It would keep making power to at least 4:1 PR.

 

[bison]

How about open valve vs. closed valve injection? The new direct injection engines spray directly into the cylinder - the heat is absorbed from the air, not the intake manifold or backside of the intake valve. Using a larger fuel injector to spray the same amount of fuel, closer to and after the valve opens will mimic DI. Use a larger injector with a 40% duty cycle vs. a smaller injctor with a 80% cycle.

How about it? Id love to see it. It would take a lot of special expensive stuff to do it. The detonation potential is gone at least.

 

[Jerryl]

How about it? Id love to see it. It would take a lot of special expensive stuff to do it. The detonation potential is gone at least.

I don’t think he is implying "direct injection" . . .
He is talking an injector that is BIG enough to be able to supply all the required fuel . . . while the intake valve is open . . . vs spraying the back of the valve before it opens . . .