New Stealth cam fitted and a couple of issues??

[TVR Beaver]

Hi All… Just had my V8D Stealth cam fitted by Rob and team and have given the car a blast and must say I‘m very pleased with the result… I also had matched manifould, trumpet base, 72mm Plenum and smooth bore 90 deg pipe fitted whilst with them…
Above 2K the power just keeps on coming and you can put your foot down to the carpet and the car now responds all the way!....
Before the car was running it’s original cam (500 Griff) and was going well with about 280 bhp… it was showing signs of the lobes going when the guy’s did my white metals, so I decided to get it changed at the same time…The ‘before’ car ran quite quick anyway but was great on tickover and hardly any shunting… since getting it back, I now have shunting or missing up to say 1700 rpm and the tickover is very lumpy and has dropped to 800 rpm?
Anyone else had these issues and any thoughts on improving tickover in particular?.... the car stalled at the lights today the tickover was that poor… it’s never done that before!!...
.
I will obviously call Rob Monday to discuss.. but just thought someone may have had the same experience and fixed it?? Cheers

[Chimjunkie]

The Stealth cam is a superb compromise between power and driveability. The rough running you are describing is prob due to something else. Best give Rob a call.

[Pupp]

That's quite a lot of changes without mentioning anything about setting up fuelling to suit...

[GreenV8S]

Pupp said:

That's quite a lot of changes without mentioning anything about setting up fuelling to suit...

Yeah.

[TVR Beaver]

Setting up the fueling?.. how would you do that?.. are you just talking pressure... or re-map????

[V8 GRF]

I think after that work/modification to the induction it needs a re-map.

[blitzracing]

Shunting is normally the ECU trying to compensate for an over rich or over lean situation. The ECU will always try to keep the catalysts happy (I assuming this is a cat car), but it seems to have problems keeping the mixture in line when longer cam durations are used. Also an air leak in the air intake or plenum area will also make the engine really rough at idle, as the ECU sets the overall mixture then, and extra air messes this process up. Id personnally find a 400 ohm resistor, and replace the tune resistor on a temparary basis, to run the non cat map. Id then set the CO trim on the AFM for a good stable idle and try a short low speed test drive. If it runs OK, then chances are mechanically everything is OK, and you need to look into mapping or fuel pressure. As a matter of interest, if its a V8 Development set up, they still have a couple of modified AFM's of mine. These are have adjustable outputs, and even though they did not produce the desired extra BHP, they do allow simple considerable trimming of the low speed mixture. Basically you can wind the output up or down and observe the lambda switching to the point the ECU can no longer compensate, and then back it back again until the probes start switching normally again (this is the point when the high / low switching time is even), and see if the drivability improves. If this works it points towards needing mapping. Tweeking the fuel pressure is a simplistic way of going about it, you simply get the pressure to get full load fueling correct, and then hope the ECU can keep it in trim below this. If it cant the car will be a pig to drive, and may fail MOT's on emissions. If this does not happen, then job's a good un!

Mark

Edited by blitzracing on Saturday 5th September 20:00

[TVR Beaver]

Most interesting.. been out tonight and had to drive everywhere above 1800 / 2000 to stop the problems... Not an issue on the open road but come into vilages / towns and even off of rounderbouts and it's hammering the drive chain... I'm around the Leeds / Bradford area... does anyone know of persons around here who could set this up????

Edited by TVR Beaver on Sunday 6th September 00:29

[v8 racing]

TVR Beaver said:

Most interesting.. been out tonight and had to drive everywhere above 1800 / 2000 to stop the problems... Not an issue on the open road but come into vilages / towns and even off of rounderbouts and it's hammering the drive chain... I'm around the Leeds / Bradford area... does anyone know of persons around here who could set this up????

Edited by TVR Beaver on Sunday 6th September 00:29

By all means give us a call tomorow, cant see what has happened but it certainly wasn't like that when you picked it up or i would have hoped you would have said something, the only shunting i found on your car was around 1000rpm in fifth which i would expect, certainly not as high as you are saying, you could try disconecting the vac advance pipe for now that should help a bit, as for hammering the drive train... something serious must have gone out of tune.

[TVR Beaver]

Will do!... I have tried the plug leads and one did push further into the cap so will try again... I did notice it a bit when I picked it up but thought that was how it was? and when your thrashing it about to see the diff a new cams made, may be you don't pick up on it as much?... but taking the other half out last night nice and steady like... she even commented on the 'metalic noise' as it rattled the drive and how jurky it was...other than that.. it's great although I'm not sure if the old clutch aint slipping a bit!!! will call you Monday... Cheers... John

[TVR Beaver]

Think I've found the problem... went up on the moors and did as suggested above, removing the advance pipe... think it made a differance but would not pick up as good as you would expect... so tried it twice with the pipe and twice without... but whilst I was messing I put my finger in the idle screw hole in the plenum and I could feel a vaccume!!... it was leaking!.. so down to the garage on the main road and bought some chewing gum... stuck this into seal the leak and much better... still does not like 1500 in 3rd but sure it was like that before!.. great news... so came back home and removed the now liquified gum... the tickover is also poor so tried to adjust it using this screw... the book says 2 1/2 turns out.. think it's now 5 1/2 turns but it does not appear to do much?? how do you adjust tickover?.. there is a small grub screw used as a stop on the butterfly... do you use this?...
Anyway.. pleased my shunting has near gone... when Rob set it up it probably had some grease on it that sealed it for a while,, that's obviously gone now and as said above... it don't take much of a leak to upset things!!!...Will still call Rob tomoro to make sure I've not upset things messing with screws,,, I have some thread lock that I'll use on the thing and will also make a cap just to be 100%...Cheers....

[TVR Beaver]

Quinny... my tickover is poor but it may not have been 100% before... it is steady on the rev counter but you can hear the engine doing all sorts of things.. before it was a nice burble with the odd falter if you know what I mean??... I asked Rob if he thought a re-map would be ness but he didn't thinks so?... can you remember your thoughts on the cam?... was your orig before?... .Basicaly my car pulled from 1K to 4.5K and gave you a low down kick in the back... where as now, the powers gone higher.. and with the mod's on air flow, it's breathing a lot better so reving free'er.. but not sure if low down it hasn't lost a bit of it's grunt?...
I'll see how it goes now.. did hear a lot on over fueling using diffo chips so not going to jump into that... get this one right first!.... cheers..

Edited by TVR Beaver on Sunday 6th September 22:03

[TVR Beaver]

1500 same as mine.. but only in 3rd for some reason?????

[blitzracing]

You need to set the base idle by bunging of the rubber pipe that leads to the stepper once the engine is warm. Then restart the car and wind the base idle up or down to get about 650 rpm, and make sure this is stable but if it keeps varing you may still have an air leak. Then remove the bung and the tickover should lift a few hundred RPM, depending on the chip mapping. As for the tick over smoothness, the ECU constantly sweeps the mixture rich / lean to keep the catalysts clean, and this leads to quite a rough idle as the ecu keeps trimming the mixture,( more so on tuned engines) but it should not misfire as such. The non cat fuel map is much smoother, but this wont pass an MOT.

[TVR Beaver]

When you say base idle... Is that the small screw that acts as a stop to the butterfly mechanisum?? And where should the the screw I'm talking about be... book says 2.5 turns out?

[blitzracing]

Thats the screw, but 2.5 turns is just a basic setting on a stock engine. The thread is very fine, so you can wind it up and down some way for a larger effect

[spend]

Are you sure about that!

The throttle stop is a small screw accessed from below with a fine allen key, the idle bypass screw is a large one accessed from above down in a recess that originally had a blanking plug on.

There are 2 mechanisms to set the throttle stop and WOT, I have seen them really messed about with The mechanics of the throttle & bypass are not complex, but I have witnessed many that have been bodged, you really need to set up the whole lot all in one go IMHO. Yes there have been plenty of examples of the idle being set by holding the throttle open with the stop The idle bypass may have been clogged - removing the plenum and giving the screw & passage a good clean may well fix the problem (the static bypass valve gets gummed up over time IMHO)

Do make sure the travel on your throttle and cable are nice & smooth whilst you're in there Wouldn't be the first wild goose chase down to a sticky throttle cable... as well as checking the TPS adjustment.

BTW both ends of the stepper by pass hose stubs need to be plugged IIRC you can't rely on the stepper being closed.

[TVR Beaver]

No... I get it now... The small one is to set the butterfly slightly open (do you know this setting?)... The large one (idle tickover) is the one you refer to as the base screw... and having blanked off... it's this you use to get to 650..... .. then re-connect but after stopping / starting engine so it re-calibrates.... Okay... think I've got it (see what you get when you talk with Mupetts!... I'll try improve!!)... Cheers...

[TVR Beaver]

spend said:

Are you sure about that!

The throttle stop is a small screw accessed from below with a fine allen key, the idle bypass screw is a large one accessed from above down in a recess that originally had a blanking plug on.

There are 2 mechanisms to set the throttle stop and WOT, I have seen them really messed about with The mechanics of the throttle & bypass are not complex, but I have witnessed many that have been bodged, you really need to set up the whole lot all in one go IMHO. Yes there have been plenty of examples of the idle being set by holding the throttle open with the stop The idle bypass may have been clogged - removing the plenum and giving the screw & passage a good clean may well fix the problem (the static bypass valve gets gummed up over time IMHO)

Do make sure the travel on your throttle and cable are nice & smooth whilst you're in there Wouldn't be the first wild goose chase down to a sticky throttle cable... as well as checking the TPS adjustment.

BTW both ends of the stepper by pass hose stubs need to be plugged IIRC you can't rely on the stepper being closed.

On the pipe... instead of blanking both ends... can't you just clamp it?????

[Slacey]

TVR Beaver said:

On the pipe... instead of blanking both ends... can't you just clamp it?????

Yep, that's how I've seen it done (and done it myself).