What's your RV8 output on the rollers?

[Transmitter Man]

Normally aspirated engines only.

At what rev's was peak output attained?

I'm very aware there's much more to sheer output such as drivability but am interested to know what this engine once modified is capable of on a street driven car.

Phil
79 De Tomaso Longchamp GTS

[dnb]

Here's my latest dyno plot. It's a bit odd because there was an intermittant misfire and the clutch slipped a bit mid run. Both problems fixed now, but a few more drivetrain problems emerged afterwards... Other than these "little niggles" it drives very well.

Edited by dnb on Wednesday 17th December 21:03

Edited by dnb on Thursday 18th December 21:02

[trackcar]

^^^ are you sure you're not getting confused with your time on the rollers at the growl Dave? there was no misfire or clutch issues when you were here. the graph is a strange shape cos thats what your induction system produced, and it was the same graph every run. it was at the growl that your car had the problems iirc ..

[Transmitter Man]

Hi DNB,

That's pretty good and interesting that it's in a TVR. Would that be a 4.5 or 5.0 litre?

I'm going to look at a 4.2 litre TVR wedge this weekend with a reported 250bhp at the wheels after a test and tune on the rollers however it is a 1988 car so I image an earlier injection and ignition system!

What is the typical stock output of your model TVR?

As your rolling road operator has picked up on this I would like to ask if there are any strength issues in earlier TVR RV8 blocks and if not are similar results, or better obtainable from the 4.2?

I believe the 4.2's are a little more free reving than the larger capacity engines!

Thanks.

Phil

[Number 7]

My 4.3 Wedge (certainly not stock) just about hits 300 calculated at the flywheel. I'll dig out a dyno sheet to post. However, to get those numbers, it's had upped compression, big valve heads, 45mm shortened trumpets, 72mm throttle disc and a Motec ecu controlling fuel and ignition. Where's this Wedge that you're planning to look at?

7.

[dnb]

Joo - there were definite clutch issues on your rollers, admittedly not fully slipping like at the Growl, but definitely being problematic. (Edited my original post for clarity "died" was too strong a word) The car was completely transformed when the new clutch went in - the power delivery lost the silly "step". We cured the big misfire with the HT lead you made me, but the other leads were also dodgy. Not something you'd notice until after new leads were fitted and the mixture "wobbles" in the datalogs went away. Neither issue would affect peak power and torque by any significant amount. (And I did sort out proper intakes instead of the Blue Peter recycled bits - this should have a more observable effect )

I did indeed have really big problems at the Growl. The clutch gave up clamping completely there, and the diff finally gave up on having pinion bearings...

Transmitter man - it's a 5 litre. Typical output is 270 bhp for a standard one in top condition.

Edited by dnb on Thursday 18th December 21:10

[spend]

430 sounds like a later TVR Engine. Aren't the 420 wedges the ones with tasty NCK built engines (cosworth pistons...) or are they also Pandoras boxes (strip it & see)?

[trackcar]

forget the bit where it says 4 litre, i never changed that from when it had its old engine in, its a 5 litre now.

Edited by trackcar on Thursday 18th December 22:43

[Transmitter Man]

After speaking with aa TVR SEAC owner he was saying it's the RV8's head's which let it down and even with porting high HP is limited.

I believe the late blocks are stronger, buy one really needs some aftermarket heads with raised ports etc to get real high flow figures, that and the rest of a suited parts combo.

Did that wedge start out as a 4.0.

I was introduced to Wildcat Engineering who are quoting some serious RV8 numbers, albeit with their own block & heads and not doubt a price to match.

Looking at the examples above then 300-350 bhp is probably near the limit on a normally asperated engine without it becoming untractable in a traffic jam!

That really answers my question.

Going to view the 420 for sale in PH.

Phil

[rev-erend]

The limit for a RV8 seems to be around 370 bhp for a 5.3.. for a normally aspirated car..

Many be someone beat that by 10~20 bhp but not really heard of any road car engine beating that..

[spend]

Thats the RV8 inlet manifold limit, not the heads IMHO. Plenty of NA 400+ cars with throttle bodies in race spec over the years AFIK?

[Transmitter Man]

Not looking at race spec, it has to hold temp in a trafic jam and be able to be driven by the boss, I mean wife.

Thanks.

Phil

[spend]

The point was that the EFi manifold is more of a limitation than the heads in many cases. There are plenty of well ported larger valve RV8 heads which are restricted by the manifold/TBase/plenum, I wouldn't be scrapping the heads until you want far more than 400bhp IYSWIM?

[Transmitter Man]

Hi Dave,

Sorry if I got the wrong end of the tree.

I understand re the EFI and intake limitations.

Many thanks.

Phil

[dumbfunk]

My internally standard 1998 Griff500 made 302bhp @6k - I'm assured the road is extremely accurate but was more pleased with the perfectly shaped power curve than the headline figure. It certainly has always felt extremely eager to rev in use.




dumbfunk

[Markh]

perfectly road friendly

Edited by Markh on Sunday 21st December 18:00

[Graham]

spend said:

Thats the RV8 inlet manifold limit, not the heads IMHO. Plenty of NA 400+ cars with throttle bodies in race spec over the years AFIK?

Indeed the only thing stopping my 5ltr race engine making 400 bhp is the class limit and the stock crank... with a steel crank ( allowing higher rpm) 400+ should be achievable, at the moment the power is still climbing when we hit the rev limit ~6400

Thats on TB's and well ported heads.


other than some low speed shunting its fairly drivable... and still on a stock griff flywheel and 3 season old clutch !!!!

Edited by Graham on Monday 22 December 23:40

[dinkel]

Transmitter Man said:

Not looking at race spec, it has to hold temp in a trafic jam and be able to be driven by the boss, I mean wife.

Thanks.

Phil

The boss . . . wow, a wife at the wheel in a SEAC: how cool is that!

The 5 litre I saw in the red Spa6 Rover P6 had 435 reliable brake up front. The yellow Dutch SEAC had a hot cam but wasn't keen on a steady idle.

Isn't 275 / 300 just enough to scrap every Pork in the area Phil? They are light cars and I expect an excellent setup will do much more than the 25 hp extra.

A.

[rev-erend]

My G/F drives mt SEAC all the time .. when I'n had a few too many drinks..

[jmorgan]

Bit o fun at the Wedge Fest. Cannot say how accurate theses are but 4.2.
OK, worked out by somehow from the second one.

And the other one.


Perhaps better people than me can interpret them. DJE motor with as much as I could afford at the time.