Chimaera Tuning - More Questions

[HarryW]

rev-erend said:

240 bhp .. think you might be a bit high there..

Not unobtainable, by a long chalk, however it will never have the torque the bigger engine can give you. It will rev more sweetly and could be considered to be a better engine for road use in some peoples eyes .

Rev having seen your beast on the rollers the week before last, I can confidently state there are 4ltrs out there putting similar power out , but then again not the torque.

Harry

[Nick P]

roadsweeper said:

rev-erend said: roadsweeper said: shpub said: The Rover V8 is a strange engine as it seems to like a bit of back pressure. The idea of tuned exhausts etc do not seem to apply. I am sure that given enough money that some improvements can be made but it is not really cost effective. Decatting (all the cats) does allow some more agressive fuelling to be done which will give a bit more power but usually at the expence of emission failures at MOT time. The 520 has fractured/destroyed exhaust systems and surprisingly does loose a bit of power when the noise increases as a result. Its pull and grunt is restored when the exhaust system is sorted out. I have modified it though by adding an additional small silencer to the output of the standard big bore box. Yes adding a second silencer did help! As the engine is producing 400+ real bhp the exhaust doesn't appear to be much of a limitation. Had to do it as the car was hitting 117 db! It now comes in at around 104-5. I have heard/know of a couple of cases where power has been lost with a modded exhaust but it is very dependent on the car. If you want it louder then a straight through is the way but be aware excessively noisy cars are illegal and plod have been known to pull people over as a result and issue an order against the car. Mainly max power types but something to think about. Cheers, very helpful. Essentially then, my choice is probably between option 1 (sleeved silencer) and option 2 (de-catting). I think I might just got for the sleeved silencer. Then later an improved induction system and Mark Adams chip and tune. That should get me up to around the 240 (real) bhp mark I think. 240 bhp .. think you might be a bit high there.. Yeah, it's possible. I based my estimate on reading Tower View Racing's website. Apparently a typical 400 makes 200-210bhp. Figure in improved induction, a chip and tune and 240bhp might be on, particularly if you're starting from 210bhp. I certainly wouldn't stake my house on it though.

I think that 240bhp is definitely on....mine is giving 216 totally standard, so with a bit if tweeking i reckon i could be there

[gazzab]

So those thousands of pounds that chap in EVO mag spent on an exhaust for his rover engine in his capri were a waste of money?

[chimhunter]

Last time I was down at Austec they explained that to get a proper tuned, equal length 4-2-1 (per bank) exhaust unde the bonnet in the Chim was an impossible nightmare. When you see what they do to get the equal length tubes into place, and the space they take up, you can understand why.

That's before you start talking about Steve's experiences with back presure and his 520.

Rob

[slikk]

Might be getting the wrong end of the stick here, but surely getting more air into the engine is the way to easy power - is there not a "quick fix" for this??? (excluding NOS of course)i.e. twin plenum etc.

[Cosmoschick]

roadsweeper said:

Some people seem to think I'm crazy...

Err... As in contemplating a Tuscan in a colour other than black!

Look, get yourself down to Austec in sunny Sussex and I'll buy you a coffee while you wait for your Chim's mods to be done and mine to be serviced! And the main topic of conversation...why black Tuscans of course!

[chimaera]

Some info about what I did to my Chimaera (1993 4ltr) Dropped out the exhaust system and cut the silencer out at the pipe joints - a 9" angle grinder is perfect and results in a clean straight cut. Ensure that the system is clamped in position so it does not move whilst you are doing this!! Buy a length of straight exhaust pipe from any motor factors (approx £7.50) align the new pipe in the gap thats left over then seam weld it together - tig welding is best.
Refit to car. Turn engine on an prepare for EVERYONE to look at you when out and about. Without doubt the noise helped to sell the car - first person bought it without a test drive as soon as I turned it on!!
I had this mod on my car and was sound tested at a few Sprint events - 104.5dB. Much too loud for alot of English tracks, but legal for those in Scotland and also for sprinting under blue book regs.
I have a video clip of the car doing a standing start at East Fortune (But don't know how to put it on Pistonheads as it approx 11MB) and can also provide photos of the mod in progress if anyone wants them.

Good luck and if you want the photos e-mail me at the adress in my profile.

Cheers,
Scott

[shpub]

gazzab said:

So those thousands of pounds that chap in EVO mag spent on an exhaust for his rover engine in his capri were a waste of money?

Yes and no. Is it going to be any better than a standard TVR design? I doubt it or if it is by very little. If he had to get a custom exhaust made with headers then that can very quickly get into four figures.

[shpub]

roadsweeper said:

Yeah, it's possible. I based my estimate on reading Tower View Racing's website. Apparently a typical 400 makes 200-210bhp. Figure in improved induction, a chip and tune and 240bhp might be on, particularly if you're starting from 210bhp. I certainly wouldn't stake my house on it though.

I wouldn't either but if you have 216 to start with that is a good sign. Induction and chipping will make a big difference irrespective of the final BHP figure.

No substitute for cubic inches or 8 throttle bodies though

[wixer]

I'm fortunate to work in the car industry at the concept/design level and as such, have a wealth of knowledge to tap into regarding such things as engine tuning, (especially as we make the engine). I spoke to a guy last year who works in exhaust design/development and also used to own a Chimeara, about improvements to the exhaust system on a Griff/Chim. His first piece of advice was to do away with the pre-cats, as these, he felt, were the most restrictive and are only there to get the emmision levels down from cold start asap, this is a legal requirement. The main cat flows pretty well and for MOT reasons is probably best left alone. His second piece of advice was to replace the cat manifolds with the earlier pre-cat manifolds with welded in bosses for the lambda sensors. As far as an exhaust system goes, he said the standard TVR exhaust is pretty good and not much more could be done to improve it, other than make it a twin system all the way through, something similar to the Zertec system that's available.

[N17 TVR]

HarryW said:

Not unobtainable, by a long chalk, however it will never have the torque the bigger engine can give you. It will rev more sweetly and could be considered to be a better engine for road use in some peoples eyes . Rev having seen your beast on the rollers the week before last, I can confidently state there are 4ltrs out there putting similar power out , but then again not the torque. Harry

I guess its what you need / want the car for, personally I have yet to be in the position where I thought I really NEED another 1000cc.

I have got a 4.0 HC and spent all my Mark Adams money on a) smoothing out the power curve b) regaining any 'leaking' power c) making the car much smoother to drive as the higher cam made it a tad lumpy.

Unless you are either a) a real track day demon or b) a traffic light Schumacher c) constrained by a small penis and/or an inferiority complex it should be enough.

There is always something quicker than yours.......

p.s. and yes I did have my exhaust done because it helped compensate for option C) above

[roadsweeper]

N17 TVR said:

HarryW said: Not unobtainable, by a long chalk, however it will never have the torque the bigger engine can give you. It will rev more sweetly and could be considered to be a better engine for road use in some peoples eyes . Rev having seen your beast on the rollers the week before last, I can confidently state there are 4ltrs out there putting similar power out , but then again not the torque. Harry I guess its what you need / want the car for, personally I have yet to be in the position where I thought I really NEED another 1000cc. I have got a 4.0 HC and spent all my Mark Adams money on a) smoothing out the power curve b) regaining any 'leaking' power c) making the car much smoother to drive as the higher cam made it a tad lumpy. Unless you are either a) a real track day demon or b) a traffic light Schumacher c) constrained by a small penis and/or an inferiority complex it should be enough. There is always something quicker than yours....... p.s. and yes I did have my exhaust done because it helped compensate for option C) above

Well, personally I'd just like a bit more performance from my Chim and adding an extra litre might be the most cost effective way to do it. My main gripe with the car currently is that the acceleration really drops off into three figures and it's a bit lumpy at low engine speeds. Of course, it also doesn't feel particularly well planted into three figures, but I can't really do much about that at the moment.

I also see the benefits of having smoother performance and better throttle response, so it's really a case of weighing them up against each other. Plus, I'd really like the car to sound even better.

Oh, and for your information, my inferiority complex is because of my small tackle, so there!

[N17 TVR]

roadsweeper said:

1) My main gripe with the car currently is that the acceleration really drops off into three figures and it's a bit lumpy at low engine speeds. 2) I also see the benefits of having smoother performance and better throttle response, so it's really a case of weighing them up against each other. 3) Plus, I'd really like the car to sound even better. 4) Oh, and for your information, my inferiority complex is because of my small tackle, so there!

1) Mine doesn't (maybe the high cam makes the difference ?) and has been more than happy (in controlled & legal conditions & ) up to 135mph and Im not sure how often i will need much above that

2) Mark Adams gave me both for a lot less than the cost of 'upgrading' the engine to a 5.0

3) $130 exhaust Mod does that

4) I keep getting adverts for creams & tablets that guarantee a resolution for a reasonable price

[roadsweeper]

Cosmoschick said:

roadsweeper said: Some people seem to think I'm crazy... Err... As in contemplating a Tuscan in a colour other than black! Look, get yourself down to Austec in sunny Sussex and I'll buy you a coffee while you wait for your Chim's mods to be done and mine to be serviced! And the main topic of conversation...why black Tuscans of course!

Heh heh, why do I get the feeling you're used to getting your way Roz?

Talking Tuscans over a coffee sounds good but it will be a while before I make a visit to Austec I think. I use SFR Engineering in Cheshire for my servicing (Shane is just down the road and does a good job) but I don't think SFR have a rolling road so I might well travel down to work (London) in the Tiv sometime and nip over to Austec for a tune up!

[RichB]

Roadsweeper - quick question, what do you iunderstand the difference between a "sleeved exhhaust" i.e. sprts exhaust conversion and a sports silencer? O wpould have thought they were the same? Rich...

[roadsweeper]

RichB said:

Roadsweeper - quick question, what do you iunderstand the difference between a "sleeved exhhaust" i.e. sprts exhaust conversion and a sports silencer? O wpould have thought they were the same? Rich...

This was a mistake in my earlier post. The sports box conversion SFR Engineering offer is actually a modified (i.e. 'baffling reduced') standard box.

[patriot7]

Hi,

Just a point on you post, I have had the pre cats removed from my car and it is more responsive and a noticable amount more torque, but £366 + vat at austec what a rip off. £200 + vat by ian lambert at Torque TVR in middlewhich. Give Him a call he is far cheaper than these big names out-there.

[900T-R]

That must take the biscuit as thread resurrections go...

[Chimjunkie]

900T-R said:

That must take the biscuit as thread resurrections go...

Indeed, quite impressive Thought the search only went back a few years?

[spend]

Chimjunkie said:

900T-R said:

That must take the biscuit as thread resurrections go...

Indeed, quite impressive Thought the search only went back a few years?

Google is your friend

site::www.ph.com/gassing and a free evening...