Serious power loss (timing?) with heat soaked JRSC manifold

Hondata installation questions / answers / issues.
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AndyE
Posts: 124
Joined: Fri Aug 23, 2002 2:39 pm
Location: Saint Louis, MO

Serious power loss (timing?) with heat soaked JRSC manifold

Post by AndyE » Wed Sep 04, 2002 3:13 pm

I have a JRSC + heatshield, and regularly run 140-150 deg. F idle intake temps puttering around town with 90-95 deg. F outside air temperature. On full boost, it will peg up to 200 deg. F or so, measured with an Autometer electronic IAT gauge (responds much more quickly to rapid temperature changes than the IAT sensor reading in Hondalogger).

This high intake temp in hot weather is no big surprise, since nothing is intercooled. And it runs great, even when that hot, for the first few minutes I'm driving. However, I'm having *serious* power loss after puttering around for a while and getting everything heat soaked. I realize, of course, that hot air is less dense, and that this will cause a decrease in power, but this is much more power loss than a simple decrease in air density should cause. It feels like the ECU is aggressively retarding the timing, 'cause my throttle response also turns to crap.

Does the Honda ECU pull out timing at ultra-high intake temperatures? Or to put it more generally, what parameters does the ECU alter based on the output from the IAT (Intake Air Temperature) sensor?

-AndyE
'99 EBP Si
S200 w/everything|12psi JRSC|Heatshield
AEM CAI|Kamikaze headers
Custom (quiet) 2.5" exhaust
Quaife LSD|JUN 9lb flywheel|ACT XTSS clutch
Eibach Pro-Kit/KYB AGX
Full polyurethane bushings/mounts
OZ 16x7 Superleggera + Sumi HTR Z II

ronin
Posts: 20
Joined: Sun Aug 18, 2002 4:10 pm
Location: Secret Services, Tampa FL
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Post by ronin » Thu Sep 05, 2002 8:44 am

i assume you are using the m62 right? 8-10 psi? is that with an endyne pulley, oversized crank or jaxon boost upgrade?
do you take it all the way to red?
Long live the silver box!

AndyE
Posts: 124
Joined: Fri Aug 23, 2002 2:39 pm
Location: Saint Louis, MO

Post by AndyE » Thu Sep 05, 2002 9:04 am

It's the standard blower from the JRSC kit for the Civic Si, with an Endyn 8-10 lb. alternator stepper pulley.

And I don't know whether it's relevant to the topic, but yes, the rev limiter and I are well acquainted...I visit it often.

ronin
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Joined: Sun Aug 18, 2002 4:10 pm
Location: Secret Services, Tampa FL
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Post by ronin » Sat Sep 07, 2002 4:13 pm

high revving on the blower, with increased intake temps, esp at high revs causes the air to begin cavitation. that and the blades of the blower heat up and cause a reduction in efficiency. it shouldn't be too bad with where you are right now tho. 200 sounds about right for that setup. if you really want some power out of it, throw on a 25 shot dry, makes GREAT power (have seen 47 whp), with that extra hot boosted air.
you DID remove the jaxon relay box from the map and iat sensors right?
Long live the silver box!

Rex
Posts: 5
Joined: Sun Sep 08, 2002 3:46 pm

Re: Serious power loss (timing?) with heat soaked JRSC manif

Post by Rex » Sun Sep 08, 2002 4:42 pm

Heh, I've become hounded by heat issues since I got my hondata and the temps here went above 80 degrees. (also have a jrsc + 8lbs). I live in Vegas, and already talked to Doug about this a bit.

I don't have an IAT guage, but I've been accessing the heat with a little infra meter from radio shack. On 100+ days temps off the intake read as much as 200 but not much lower than 160. Headers 400 (with header wrap) Manifold area, 200, radiator 200-210. Monday, I'll have a coolant temp gauge in (140-280) and I'll get a little more info on what's going on while driving.

It's going to be Fall soon, and I expect my heat issues are going to decrease significantly.

here are the things I've done so far with my rating of success.

JR 160 thermostat - works, but really doesn't do much to combat temps where the stat is going to be open all the time anyway. (like in 100 degree temps) If you want your engine to be cooler at modest temps it's okay, but at extreme temps it's no better than the oem, because the whole systems/radiator/ fans are already working at maximum.

Header wrap - I think it slows down the heat soak in the beginning, but I never saw a drop on the temp gauge over the long run.

Redline WaterWetter and coolant/water ratio change. Best results of anything I've done. Lowered coolant ratio to 30% water up to 70%. Added appropriate amount of Wetter. Car definitely runs cooler, and as a result longer. Still doesn't help when outside temps are really excessive 103 or so on up. (BTW, honda doesn't recommend going below 50/50 ratio, so try at your own risk)

Something new I'm trying - insulating the fuel line. I've read if heat becomes excessive, it can convert the gasoline to vapor/ or cause bubbles, which can screw with the flow of course.

The other thing I'm doing is going to a 3 inch intake (completely insulated) into the fender as opposed to in the engine bay.
I'm also going to insulate the fender area with a half inch of stryafoam. I just haven't been successful with shielding it very well inside the bay. This should be finished by next week I hope.

(of course there's always a Fluidyne radiator, but that's the most expensive option and it will be last - and oh an oil cooler)

I can't think of much else except spraying NO2 at it after that. (or moving to North Dakota)

(no I don't have datalogging)

ronin
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Joined: Sun Aug 18, 2002 4:10 pm
Location: Secret Services, Tampa FL
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Post by ronin » Sun Sep 15, 2002 2:57 pm

i am in florida and temps get high here too, in the colder (below 70) weather, the blower loves to spin, and it loves cold starts. in the hotter weather (90+) it would bog, and not start on the first turn, and would make no top end. another trick i did was to thermo wrap the intake pipe (modified aem cai). took me 2 little boxes of cool-it (thermo-tec) to cover the intake (abotu $30). i know at wot the air coming in is not the engine air, and is not nearly as warm as radiant sources, but without an i/c, every little bit helps.
Long live the silver box!

Rex
Posts: 5
Joined: Sun Sep 08, 2002 3:46 pm

Post by Rex » Sun Sep 15, 2002 9:24 pm

I just finished a custom 3" intake into the fender. I'm thinking i should have done this a long time ago.

Although wheelspin was particularly bad at the track, I went through my timeslips, and my mph were on average 1 to 2mph higher than ever before over the 5 runs that I did.

BTW, I used a 90 degree elbow mandrel-molded coolant (rubber/urthrane?) tubing , and cut up an old 3 inch akimoto intake tubing. The 3" gives very little flexibility that is, it is a tight fit, but the flexible elbow made it a lot easier.

One other thing - I drilled lots of extra holes through the rubber fender bottom so it would be sure to get plenty of air, and I sprayed the whole inside of the fender with 1200 degree high heat ceramic dupli color paint as well to block both possible engine heat, and tire heat from the wheel well. Now I'm in the process of insulating the tubing in the engine bay going to the intake.

Carchitect
Posts: 82
Joined: Thu Sep 19, 2002 11:14 pm
Location: Dallas/Ft.Worth

Post by Carchitect » Mon Oct 07, 2002 9:12 pm

I also have a customer of mine that gets his JRSC heat soaked reletively easily. Since the battery was relocated to the back this gave me some room under the hood. The throttle body is closest to the battery so I'm planning on making an airbox where the battery resided and installing a small hood scoop. This will bring in fresh air from outside since the aem or other cold air intakes still get heat soaked very quickly (even heat wrapped)
Experience is what you get when you don't get what you want
08 IS350 Sport Package, Levinson, Nav, Radar cruise.
94 JZA80 6speed undergoing major weight reduction AKA 911 GT2 killer.
90 DA9 B18C5 retired auto-Xer

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