5 cylinders at 6k rpm

[Ed]

Hi all,

I hope this is a simple question to answer, my 155 HGT shows all the classic 20v reluctance below 3500 rpm and picks up nicely (although not neck snappingly like my old Type-R) above this.
However, when I get to about 5500 the engine note changes from a smooth growl to a quite rough rasp.
The acceleration doesn't drop off particularly (it doesn't get any better though) and going further just doesn't feel like you're getting any benefit from the higher revs.
Anyone got any views on this? Is it just me being unused to the note of the odd cylinder? or should I get it checked out?
What limit do you guys change at? I thought peak power was at about 6200? Am I missing something?

Thanks for any advice.

Ed

 

[judge judy]

similar problem

when i slam my nuts in the car door it hurts like hell, what can i do to to stop the pain?

judge judy

im firm but fair

 

[Si]

Where abouts in the country are you Ed, maybe one of us HGT 20v owners could compare yours with ours.

 

[Nikki]

Re: Re: 5 cylinders at 6k rpm

My engine noise changes at about 5000rpm on my HGT but this is due to the Variable Valve Timing that the HGT has. Gives the engine a bit more grunt and makes it growl slightly louder - that's my girlie interpretation of what my bloke tried to explain to me technically!!!! If you want more technical info then I'll get him to put a post on later when he's back home from work.

 

[Ed]

Re: Re: 5 cylinders at 6k rpm

I'm in Oxfordshire, if there are any other HGT owners around the area I'd be interested in hearing from them anyway!
I've just got back from a trip out to H+L engineering in High Wycombe, and they seem to think it's fine.
They were actually very good and seemed pretty knowledgable about the Bravo although they're specialists in Fiat Coupes really. They work on Fiat, Lancia and Alfa and have good connections wrt body and performance upgrades. I'd recommend giving them a try if you're in this area.
They offer a free check over on any newly purchased Fiats and even managed to top up my gearbox oil for free.

Ed

 

[Si]

Re: Re: Re: 5 cylinders at 6k rpm

Were having a meet at Santa Pod on May 18th if your interested, their should be quite a few of us in attendance.
Look out for the posts on the forum with full details.

 

[Will]

Re: Re: Re: 5 cylinders at 6k rpm

The 155 engine has a trick inlet manifold wich changes shape / length at a certain r.p.m, not as effective as variable valve timing but it does help a little and it does change the engine note.

 

[sandro]

Hi Guys,

the change in engine note on the 155 HGT is due to the variable inlet manifold geometry. There is a flap that opens/closes to have long inlet manifold at low speeds for better torque and the shortens it at high engine speeds for better power, i think the flap changes about 5000-5500rpm.

sandro

 

[Ed]

Re: Re: 5 cylinders at 6k rpm

Result, that was just the answer I was looking for.
As long as when it happens I can think "Ahh, manifold geometry" and not "wait for the valve piston tinkety plink" I'm happy

 

[Gonzalo]

VIS = variable intake system

the inlet is geometry variable... is that the VIS?

i thought the bravo had a 'VTEC' camshaft too... isnt that true?

in Honda words... it is DOHC, but is the Bravo really VTEC?