280bhp out of a 4.5 - How?

[nickd01]

So, I've been reading that the TVR power claims are a tad generous.

I've had my car tuned at Austec to ensure it's running 100% and that improved it's smoothness no-end. Unfortunately their PC wasn't linked to the rolling-road and so I don't have a power print-out, but they said it was "good" for a 450.

From reading threads here, I'm assuming "good" isn't 280bhp though!

Is it possible to acheive the factory power figures or does it just cost a fortune? What would I need to do next?

[markh]

I'm sure it can be done, my 450 is showing 273/bhp 299 flbs at the moment with just the fitting of larger injectors,ACT twin plenum and an after market ecu (coil packs etc)and mapped on a RR. pre conversion was showing 241 bhp so has shown a good increase, have some stage III heads and different cam (V8D) to fit soon and am hoping to be around the 300 mark after that.

Mark

[TVR Pablo]

I've got 282bhp/320 lb ft after doing the same work as Mark plus the Stage 3 heads and 218 cam.

I haven't tuned and RR'd it yet with recently fitted ACT manifolds and full decat, but would expect to get fairly close to 300bhp.

More than that would need to wait for a TVR Power supercharger, but it feels plenty quick already

[markh]

Hi Pablo
which ecu are you using? I've got an Autronic

[pullingpower]

I have 272bhp with just the stage 3 heads and H404 cam. No ECU mods and original plenum. Next step would probably be Mark Adams chip but spent 6K so far including engine rebuild so no rush for further mods. It's plenty fast enough anyway!

Edited by pullingpower on Tuesday 12th September 12:35

[vixpy1]

Good standard 450 is 250bhp to 260bhp..

like the guys say, with mods 280+ is possible

[TVR Pablo]

I've got the Mark Adams chip. To be honest, I was expecting more bhp from all that work, but the 218 cam is more about torque, and Mark thought the figures looked right when he tuned it. Living in London with the Tiv as my only transport meant I didn't want to compromise driveability, and the power delivery is really sweet.

[brummiewedge]

I got 296bhp outa my 4.6 in the wedge, but it does pull harder in the Chim i think thanks to the larger manifolds, low to midrange power that is, but have not dyno'd it in this car. Emerald ECU to go on this month hopefully. I have a 72mm choke ( aswell as other stuff.) on mine but that puny little hole in the AFM just before it, im hoping that ditching the AFM might give it a bit more somewhere. Just for info i had three ECU's when on the dyno, a JE, 4.0 TVR and a 4.3, the 4.3 tvr gave a good AFR across the range at 42psi.

[greg_D]

are the figures given at the fly or at the wheels?

[mongoose]

brummiewedge said:

Emerald ECU to go on this month hopefully............. on mine but that puny little hole in the AFM just before it, im hoping that ditching the AFM might give it a bit more somewhere.

Ditching the AFM altogether is a very good move,and will give increased performance throughout the whole rev range,as i found.The AFM is restrictive from something like 150BHP!! is what we found on the dyno.Spending your money on a larger AFM would also be just wasting it,when you could be investing it elsewhere.Once you have a straight through pipe in its place,it's well worth replacing the 90o elbow to plenum with an oversize 83mm silicone bend(not easily available),this will give another very impressive gain throughout,for very little outlay

[TVRobin]

mongoose said:

Ditching the AFM altogether is a very good move,and will give increased performance throughout the whole rev range,as i found.The AFM is restrictive from something like 150BHP!! is what we found on the dyno.Spending your money on a larger AFM would also be just wasting it,when you could be investing it elsewhere.

Do you mean Air Flow Meter (AFM)? If so how does the engine run without it?
Regards, Robin.

[mongoose]

TVRobin said:

Do you mean Air Flow Meter (AFM)? If so how does the engine run without it?
Regards, Robin.

Sorry Robin,yes i did mean the airflow meter.You run without one by using the throttle position sensor for a load reference on the fuel map.This can only be done with a different ecu though,such as brummiewedges Emerald,or my Omex.

[TVR Pablo]

Figures are at fly.

What else do you need to think about if changing the ECU to e.g. Omex? Does it have an effect on running at lower speeds?

Thanks

[markh]

I can only speak for the autronic, but I have found so much easier to drive, far more smooth

[brummiewedge]

The differance is that you do not havto rely on the limitations of mechanical advance/retard. You can map at any part of the rev range ignition and fuelling, ok the std Rover stuff can be mapped on the fuelling, but with a laptop you can map "on the fly". You are basically moving on 20 years as far as the technology goes. I'm expecting it to drive better everywhere in the rev range. Maybe not loads more power, but maybe a bit more here and there, and as i said you remove the restriction of the AFM which must be of benefit.

[trackcar]

Mongoose is right .. we did a back to back test on his 5 litre griff on AFM v no AFM and overlaid the traces, the 5AM meter is restrictive at any hp above 150 .. that means that it's robbing hp on even std 4 litre engines .. if you are serious about hp from your engine the first things to go should be the AFM and the restrictive elbow to the throtle/plenum. It's an easy 15bhp with no other mods on most large capacity RV8s

[crazycraig]

I've heard of people boring the AFM out, is that a viable option?

[trackcar]

erm i don't know because i've never done that, but i would imagine that the fuel slope would change and at least need rescaling if not mapping from scratch so you'd pay handsomely for that (i think current rates are £350 for a mappable chip, then the 2-3(?)hours for mapping and the same hours fo the dyno operator) .. with all the fiddling the best route imo is still to get rid of it and go aftermarket .. that way you get mapped ignition aswell of course don't forget

[TJW]

If there is a 'gause' just before the AFM, take it out, we gained 5bhp on our V8S. but kept the torque i thinks.!

[crazycraig]

trackcar said:

erm i don't know because i've never done that, but i would imagine that the fuel slope would change and at least need rescaling if not mapping from scratch so you'd pay handsomely for that (i think current rates are £350 for a mappable chip, then the 2-3(?)hours for mapping and the same hours fo the dyno operator) .. with all the fiddling the best route imo is still to get rid of it and go aftermarket .. that way you get mapped ignition aswell of course don't forget

Thanks , thought it sounded to good to be true , is it worth swapping the ridged 90' elbow to the plenum with something smoother if you've still got an AFM though?