T Sport Boom

[VVT-i 2]

Hi all,

My 2003 Corolla T Sport has an annoying problem. Whenever accelerating when the revs hit 3k there is a boom or resonance through the cabin, this disappears at 4k rpm.

Really annoying as the boom equates to motorway cruising speed in top.

Also when I release the fuel filler cap to refill the tank seems to be vacuum pressurised, blocked breather maybe? or do they all do it?

Finally I get 30mpg, jesus I use to get 28 mpg outta my Impreza! is the 30mpg normal? I do use the revs and the lift but certainly not excessively.

Look forward to your comments, cheers.

[badboyts]

dont know bout the "boom" sorry :!Removed!: but my tank is pressurised i think most tanks are nowadays. as for you mpg i only manage bout 27 to 34. i like to hit the lift :D

[Panners]

Hello,

Don't have any experience of the boom you're describing.

I also have the hiss when removing the filler cap, the old Golf GiT used to do it so I'd imagine that's simply a quirk, and if you're getting 30mpg you're quite fortunate, get about 28 in mine, regardless of my driving style.

Hope some of that was useful to you.

Cheers

[VVT-i 2]

Thanks guys, I really think I might have a problem, its annoyingly noisy at those revs, so much so you have to cruise at 85mph to stay out of the boom zone.

Considering an airbox upgrade to free up the induction, any recomenndations?

Tend to run the car on Tesco 99 RON

[Jock Fran]

Yeah I know what you mean about the resonance boom. It can get a bit annoying. But it's not horrific and it depends what you're used to if you'll even consider it noisy or not.

I'm not sure but I think there was a change on the facelift to get rid of it. If you can find out what it was you may be able to make the change to your car.

[rolley]

Sorry VVT-i 2 its a common characteristic of the car!

Between 3500 to 4500 is where quite a lot of the cars torque is being produced! So its taking in a lot of air and the exhaust note deepens (the boom your talking about)! The only way to solve this is either as you say hit over 80 or stay as close to 70 as possible! Its a bit of a git so if you slightly tick over the 70 mark your pushing the 3500 to 4500 rev bracket! Your other option is to drop it into to 5th gear!

As for mpg! At around 3500 to 4500 revs your fuel economy isn't that fantastic! If you check the constant mpg calculator on the radio your likely to be get arounfd 26-30 depending on incline or decline of the road! Best situation if you want decent mpg and no noise you'll have to stick to 60! Otherwise use the constant update mpg to see what the cars doing and play the gears! A lot of people don't rate the mpg calc for accuracy! But i think its near spot on, and has always worked out right for me when i've calculated it up!

By the way you did extremly well to get 28 out of a scooby! Everyone I speak to that has one has to have an account with an oil refinery! lmao

[Ed_Shek]

I'm getting around 30mpg at the moment!

The 'Boom' doesn't bother me though I haven't done that much motorway driving in the car.

[Captain Weirdbeard]

Hi all,

My 2003 Corolla T Sport has an annoying problem. Whenever accelerating when the revs hit 3k there is a boom or resonance through the cabin, this disappears at 4k rpm.

Really annoying as the boom equates to motorway cruising speed in top.

A slight change in internal tank pressure is normal enough when you release the filler cap, especially immediately after a high speed journey and a stop at services. If it feels like it really wants to suck when you undo it though, it would indicate a blockage in the cap's breather orifice. That's easy enough to check with a bit of close inspection.

The boom... yeah it's a "feature" on normally aspirated T Sports. The compressor is much better sorted for resonance and noise generally. Cheer up though - it's not really that bad. The rest of the car is so quiet that it stands out a bit. You should have been driving in some of the cars that were regarded as quiet 25 years or so ago. My ears are /still/ ringing.

You might find that it is possible to move the resonance to a different frequency with careful use of self adhesive sound damping materials. I'm sure a search will give you some ideas as to where to start.

[Jock Fran]

Agree about it being a noticable boom in comparison to other noises.

The Corolla has very little road/wind noise, and even engine noise below about 3.5k revs. So when you get above those revs it's quite noticable.

I had a Fiesta hire car in Portugal at the beginning of summer and the road noise was unbelievable above about 40mph. It was wearing Bridgestone Turanzas aswell - same as the CTS!