Lexusalex

On my 1993 SC400 after I do few hard runs the car start to slow down and it feels a bit like it is choking just a lilte. Its not as responsive.
I have been told Im posibly geting heatsoaked.
Anyone having the same issue?
What is a possible solution to this problem?
could it be that Im running too rich and flood the injectors so it runs slower the second time that i race?

vipsoarer

i seriously doubt its heat soak, but it could be some other things. first off id check plugs/wires/etc. in the ignition. Is the right type of fuel being used (91+ octane)? next id see if the motor is clean inside and out (check the seafoam post on the page) and lastly id make sure you have good oil in it. Old oil will break down easily after a few spirited runs and causes friction. a good clean motor inside and out lets the motor run cooler and perform better by not having the manifold clogged up with carbon deposits. and i think we all understand why to check the ignition system, if you dont have a good spark, you dont get a good burn.

heatsoak is much more prevelant in boosted cars or cars that have insufficient cooling systems for the vehicle, aka 80's oldsmobiles. if your lexus is getting heat soak something is seriously wrong with the cooling system and the heat is most likely retarding the timing. i doubt its the injectors overspraying for no apparent reason only after a few runs. doesnt seem very plausible.

got_trd

more than likely its just your iat's getting hotter after those pulls causing the engine bay to get hotter so your sucking in hotter air

Lexusalex

Well I do have a BFI. I thought it was preaty well sealed and its sucking air from the front Air chamber. But I guess Its posible

Lexusalex

I rechecked my BFI today to makes sure Im not geting any hot air sucked it. Ran car hard a few times, opened the air box and felt the air filter to see if it is warm at all to indicate hot air being sucked in. Air filter is cool to the touch, so that rules out hot air sucked in.
Any other ideas guys?

Kaiser

iTrader: (1)

Coolant and intake air temps are both a part of the timing table. The ECU....if it's like others....will pull timing for higher termperatures of both.

SCV8

The intake manifold will heat soak after idling in traffic, or shut down after a hard run.