Chamber cooling under boost

[Two Lane Blacktop]

Re: Chamber cooling under boost

I see it as a way to lesson my dependence

on the methanol injection system

and/or allow me to run more boost on 87oct.


With a 4000+lb car and a 256cid engine

I'm going to be in the boost pretty frequently.

Methanol (meth/H20) injection works because

the mixture chemically intercools & lowers the

incoming air and fuel mixture within the intake tract.


The stated goal of "lessening your dependence"

on methanol injection would not be served by

the proposed method, and at best, if effective

at all, would only potentially serve to be a

miniscule adjunct to the meth spray.


Is this vehicle going to be for street/strip,

race-only or daily-driver? "Running boost

pretty frequently" & "running higher boost"

comes with a play-now & pay-later clause,

i.e., decreased longevity. Perhaps not so

significant in a track-only/nice weather

week-end warrior, but reliability & longevity

loom large in a daily-driver scenario. 2 tons

+ 256 c.i. + boost = stress & strain, eh?


We know most of your queries are academic

at this point, and hypotheticals are meant to be

trial balloons scrutinized for validity/viability. So,

please do keep all your Qs coming!


We're here to help as your vehicle/engine combo

progresses from the blackboard-to-the-blacktop. --

[wikd69]

Re: Chamber cooling under boost

You guys are just being nice to me, aren't you, by not pointing out how simple-minded I am in my focus on cooling solutions <laffin at myself>

[CTX-SLPR]

Re: Chamber cooling under boost

Car: '64 Buick Riviera
Engine: 256cid SEFI Turbocharged Intercooled Buick V6 (3.995in bore, 3.400in stroke)
Heads: CNC ported iron heads
Cam: 212/212 Comp roller with 1.65:1 roller rockers (0.536in valve lift)
Turbo: Precision GT6162BB
Compression: 7.9:1 (really wanted 8.3:1 but with custom pistons I can't exactly just swap for another set once I got them)
Trans: TH200-4R, 2800-3200 stall
Rear: 8.5in 30-spline 10 bolt, tru-trac LSD, 3.73 gears

Primary Function: Nice Day driver, long distance cruiser, 11.5s safety limited drag car about 12-18 runs a year, maybe a bit of autocrossing.

[BlackoutSteve]

Re: Chamber cooling under boost

Make sure your cooling system is working well and plumb it for 4-corner cooling as well if you wish. (I did on my last build and it seemed to work well) but..

I think water injection will do a lot more for you than over-cooling your heads, be less effort, and better gains. Probably cheaper too.

I'm no thermodynamasist, but if I remember rightly, cast iron engines produce slightly more power than aluminum because they retain more heat.
Heat and (cylinder) pressure go hand-in-hand, so removing more heat for the surrounding materials only pulls more heat (and pressure) from your combustion chamber, lowering your BMEP.
It's all theories, yes..

But, I believe it's better to lower the temperature of the intake charge via air-to-air intercooling or ablation (cooling through evaporation).

[Groucho]

Re: Chamber cooling under boost

I ran a SBC in my Vette some years back with reverse cooling with pretty good results. 11.78 compression with pump gas. Brodix heads and intake allowed me to put freshly cooled water into 6 points on top the motor, all -8's that I hogged out a little. One on either side of the now blocked off thermostat area, either side of the dizzy, and where the heat riser area would've been. I got a Howard Stuart NASCAR water pump that has 1/2NPT holes in each leg right where the pump bolts to the block. I made a shim that kept all water from entering the block, forcing it through the holes previously mentioned. I had a -8 TEE on either sides of thermostat housing and where the heat riser was, and -8 90's at the dizzy area. I drilled between the freeze plugs for the "return" to the radiator. This all puts freshly cooled water at the combustion chamber area. See photo

http://img406.imageshack.us/img406/11/dsc00967et9.jpg

[dieselgeek]

Re: Chamber cooling under boost

the cooling idea wouldn't work, because the extra cooling needs to happen AFTER the pass, not during it. I'm still waiting to see the SEFI portion of this project though. Will happily eat my words if it runs right!! ;)