YODAONE

Denso fuel injectors on LS400's produce a wispish clicking noise as they open and close...therefore was wondering if anyone offered an engineered solution to attenuate injector noise..

Contemporary direct injection engines are even noiser..almost like a diesel...due to significantly higher fuel pressures, so noise containment solutions will prove more critical going forward

The factory solution is to use an engine cover, however the bettter approach is noise containment at the source.

While searching online with keywords "fuel injector covers" and "Injector sound attenuation" I did not find much.

I located fuel injector cover wraps by Design Engineering, Inc. located in Avon Lake, Ohio advertising; "these covers wrap around fuel injectors or sensors and will reflect radiant heat aeay from them...Cooler fuel injectors operate more efficiently and will help prevent vapor lock and heat soak."

While my primary interest was in reducing noise, it seemed logical that isolating the injectors from heat would produce cooler fuel charge, delaying onset of knock, thus allowing the ECU knock sensors to advance ignition timing for increased power and efficiency. As an added bonus decreased injector wear and easier starts where frequent starting and stopping occur.
DEI kit #010383 contains 8 injector covers.

Post installation, there was a discernible decrease in noise...after all the noise is more contained at the source, but would have been even

quieter save for the gap at the top where the injector wrap must leave a gap to accommodate the injector connector and wiring.


Installion instructions are straightforward....but we advocate disconnecting the negative ground from our cars and not the positive cable...





Here are the 8 Injector covers as received fron DEI. They consist of a durable reflective foil barrier(not shown) and a high temperature rated pliable glass fiber weave. Velcro type tabs on opposite sides on opposing ends provide custom fit for each injector...On the LS400 all 8 injectors, wraps do not cover the same, so flexible fitment is helpful.





The Injector wrap, both sides before fitment around the injectors.





This image depicts positioning of the Inector wrap around the left front injector. Fitment was accomplished by using a long needle nose pliers (suggest you do not use one with side cutter to avoid inadvertently cutting or nicking wires) and a common screwdriver with a long shank. You notice all of the exposed wires..The heatshrink tubing on the entire engine harness has disintegrated. DEI offers Hi-temperature

products designed for engine compartment wiring management ...heatshrink , pre-split and tape. Perhaps my next write-up.

dicer

You could fill the whole under hood area with fiberglass insulation that should deaden the sound.

YODAONE

Not sure how the cooling fan would evacuate heat; exhaust manifolds, intake, heads etc. from an engine bay filled entirely with fiberglass. The thermal management products here isolate the injectors in close proximity to constant engine heat: 185-212 F, (Exhaust manifold 600+ F) and the engineered fiberglass cloth with reflecting foil material is up to the task of heat isolation with secondary benefit of serving as a noise barrier, albeit not 100%.

As an aside...the main fuel line affixed to the fender well passes about 1/2 inch away from the exhaust manifold heat shield for several inches! This screams for protective covering similar to the injectors. I will discuss with DEI and present their recommendedations.

As with air, cooler fuel has more density, so with more dense air its expected with more density the fuel will burn with more efficiency and consequently generate more power..

Cooler fuel has a greater capacity to absorb heat from the inlet charge so increasing the amount of air heading for the cylinder..and the ECU will adapt.

Bentley uses the AC system to cool the fuel on its Azure and Arnage to cool the fuel..

Ferrari Lemans AC unit requires 7 HP to spin, but gain 35-40 HP..

No disputing heating fuel is not the way to increased efficiency and HP in a fuel injected engine.

Lexus could have improved noise and, thermal isolation at the injector and fuel lines, however elected not to do so.

These incremental improvements offer ways to affordably squeeze a few more H.P.

B

y isolating the injectors, fuel rails, and fuel lines from constant 200 F + will net 3 HP. and 1% increase in MPG.

You tell me why the factory doesn't think of these things...you tell me.


Main fuel line on 1999 LS400 asrtride and aside exhaust manifold heat shield. What were they thinking!? Room for improvement here.