Supercharged Chim 4.0

Supercharged Chim 4.0

Author
Discussion

v8nrg

Original Poster:

854 posts

244 months

Wednesday 19th October 2005
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I have been thinking recently about embarking on a little project to make my chimaera a bit quicker.
This would be almost completely a diy project and it would be on a limited budget.

I have seen a few superchargers for reasonable money and wondered if it would be feasible. Normal "tuning" is too expensive and will not yield the same kind of results for cash spent, so forced induction is the way to go.
And before anyone says Buy a 5.0, it would cost to much to upgrade. Also, chimaeras seem to be hard to sell currently.

So what issues are there to consider? Am i thinking along the right lines?
Has anyone else gone down this route before ?

Supercharger type - Likely to be a roots type blower, probably Eaton M90 or M112? I would prefer a twin screw type compressor but they don’t seem to be readily available.
Fueling - Bigger injectors will be needed as well as higher flow fuel pump.
What are the options for these? Would 5.0 injectors flow enough fuel?

Boost - about 5-6 psi should be ok without any changes to compression ratio or any intercooling ?

Ignition system - should be ok standard as long as its in good working order.

ECU - remap by Mark Adams or piggy back system such as a Unichip or similar.

Would i need to change the air flow meter ?
what other parts would i need to change/improve ?

What other factors are there to consider ?

cheers
Adam

trackcar

6,453 posts

227 months

Wednesday 19th October 2005
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I'm going turbo on my v8s over the winter, using a megasquirt ecu for control.

No need to change your injectors i would say .. I'm going to run my std injectors and add an extra injector upstream of the turbo impellor .. 350matt says it helps cool the impellor and hence the charge, and helps compressor sealing so less temp for any given boost pressure .. no reason why that shouldn't be the same on the supercharged version ?

as with all projects like this you'll get the doom and gloom merchants saying the chassis won't take it, the brakes won't take it, the engine won't take it etc etc .. I say just go ahead and do it, and best of luck to you

GreenV8S

30,210 posts

285 months

Wednesday 19th October 2005
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Go for it, but just as a cautionary note: if you think that the conventional route of tuning your existing engine or upgrading to a bigger engine is too expensive, I have to question your assumption that a supercharger conversion will be any cheaper.

trackcar

6,453 posts

227 months

Wednesday 19th October 2005
quotequote all
GreenV8S said:
Go for it, but just as a cautionary note: if you think that the conventional route of tuning your existing engine or upgrading to a bigger engine is too expensive, I have to question your assumption that a supercharger conversion will be any cheaper.



.. because you've done the development Peter

v8nrg

Original Poster:

854 posts

244 months

Wednesday 19th October 2005
quotequote all
Peter,

What kind of blower do you have on the V8S ?
what pressure is it running ?
where is the throttle ? filter or engine side of compressor ?

Have you got any kind of write up detailing the system and what components have been used ?

I’m no expert, so im trying to gather as much info as possible before committing to the project.

On the subject of cost, I will be aiming towards 280bhp and 280lbft (flywheel)to start with. From what i have read it would take a good standard 5.0 or tuned 4.5 to get to this level, and at a cost of over £3,000 to change my engine. My budget for this project would be half that (hopefully less), this would be done over a period of time to spread the cost and minimize the time my car is off the road.

Am i being realistic with my budget ?

jellison

12,803 posts

278 months

Wednesday 19th October 2005
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Ora race spec 4.0 will make those numbers too, but in adifferent way, higher lift cam - flowed heads, high compression etc etc - but can easiely make 300bhp from a 4.0 easier in someways that a 5.0 (as you have a stronger (as not such a long stroke) revy'er engine (6500 - 7000 easy - do that in a 500 and it will go bang).

Might cost more - but then again might not! - bloweing easier maybe as no engine stripping. Blower sounds best for you.

TR8's I raced against a while back made 290 - 320 from 3900 on 60 thou overbore = about 4.0.

GreenV8S

30,210 posts

285 months

Wednesday 19th October 2005
quotequote all
trackcar said:
I'm going turbo on my v8s over the winter, using a megasquirt ecu for control.



What are you going for - 130, 230, 330 , ... 430 ???

trackcar

6,453 posts

227 months

Wednesday 19th October 2005
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I'm going for the one bhp less than it takes to go bang... i've got to find some way of keeping up with you on track ..

GreenV8S

30,210 posts

285 months

Wednesday 19th October 2005
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Well a good turbo installation has the potential for a *lot* more power than I'm going for so I doubt that keeping up with me will be any problem. I'll try to get out of your way promptly as you come round to lap me!

GreenV8S

30,210 posts

285 months

Wednesday 19th October 2005
quotequote all
v8nrg said:
Peter,
What kind of blower do you have on the V8S?


It's an Eaton M112 (this is the biggest one that Eaton do) mounted in the Vee. You can see the general layout in the pics linked from my profile. It's slightly lower than a convention EFI plenum installation, the downside is I have more or less deleted the intake manifold which is producing some 'interesting' low speed/part throttle running characteristics which I'm still working on. The throttle is upstream, and there's a recirc valve to unload the blower for cruising. I'm running WI, and I've got provision for for an air/air intercooler (hence the big shiny tube on top) but I haven't fitted one yet.

The blower is geared down to produce about 0.4 bar boost. My goal was to produce a mild 320 bhp with a very broad power band. I figure the best way to improve performance is to use a broad enough power band to save gear changes into and out of every corner rather than going for the big numbers with a screamer. I've restricted the changes to the top end, so the bits that tend to wear out / break are all standard and therefore cheap, which I think is a big advantage over the conventional tuning route. I haven't finished setting it up or had it measured yet, but judging by the way it pulls I'd say it's producing power in the low 300s and torque in the high 300s, so roughly on target. The blower is capable of producing lots more torque than that, but the transmission would never stand it. If I red line the blower it flows the equivalent of about a nine liter engine, but the current gearing is equivalent to a mere six liters worth.

anonymous-user

55 months

Thursday 20th October 2005
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Have a look at this as well. I think the Rotrex solution would be worth investigating.

www.pistonheads.com/gassing/topic.asp?t=208934&f=8&h=0&hw=rotrex

bagpuss 996r

112 posts

224 months

Thursday 20th October 2005
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Cannot see how this is going to be cheap.Trackcar dont fancy injecting fuel int a red hot turbo if you inj after the turbo you wont need to run a seal on the conpressor. Also because its hotter after you will get better cooling latent heat of evap or something good luck with buisness could not wait any longer for nitrons sorry.

GreenV8S

30,210 posts

285 months

Thursday 20th October 2005
quotequote all
I don't think the fuel/hot turbo thing would be a problem, it's not at all easy to get fuel to light and the mixture would be extremely lean at this point anyway. But the WI guys shy away from upstream water injection because of prolems with blade erosion, is this a problem with upstream fuel injection too? Apart from that it seems like a great idea, the turbo would be more efficient (closer to isothermal) and nicely avoids having to go to massive injectors dowstream with all the part load problems that would give.

bagpuss 996r

112 posts

224 months

Thursday 20th October 2005
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The turbo throws the fuel on to the walls so you get puddling. You have injection anyway this is higher pressure so downstreem is not a prob ran water on my RX7 now that ran hot.Also mixture distribution god knows where it would go better with 2 turbos(cost again) so bar for it as a kind cold start injection i think it would be a no no.Going back to what i said earlyer the temp difference is bigger between hot air and cold fuel after the turbo so the temp drop is bigger.would be better with intercooler water one, there is that cost thing again.

>> Edited by bagpuss 996r on Thursday 20th October 21:04

350matt

3,740 posts

280 months

Friday 21st October 2005
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The reason for running a pre-compressor injector is that is cools the charge and atomises the fuel / air mix very well plus give you a side benefit of sealing the compressor better.

This is used at cosworth on the Indy car engines which admittedly use Methanol which does tend to evaporate more easily, however if this system didn't work how do you explain many supercharger installations out there running a carb in front of the blower?

Bear in mind that water is not fuel it takes a lot more energy to vapourise

Matt

bagpuss 996r

112 posts

224 months

Saturday 22nd October 2005
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HI matt never said it wont work however we do not run points any more if poss, janspeed ran a single su on a v8 in 70/80s . Dont understand the sealing issue how fuel can seal a compresser at 110000rpm not sure and what for what are you sealing against.As far as i know the indy issue is only cos intercoolers were banned and the high laint of evap is greater.Now the carbs in front of a supercharger is another cost thing and easy way of doing it.The water thing is that you will lose power if it is not needed, however if you run a higher compression or boost it will stop the onset deternation so cooling the intake charge. Thanks for making me think for a change interesting coversation.

>> Edited by bagpuss 996r on Saturday 22 October 06:10

daxtojeiro

741 posts

247 months

Monday 24th October 2005
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Have a look at my site for info on installing a blower onto an RV8 based engine, I did it to my 3.5, same principles for all engine sizes.
I have spoken to Jooles before about this, I favour water/methanol injection down stream of the turbo and bigger injectors for fueling. Dont really see why youd want to seal the turbines better if you only need low boost anyhow, just buy a better turbo in the first place. Also I cant imagine that the fuel would flow evenly to all 8 cylinders from the turbo, Id expect there to be some problems there, but Ive never tried it so I cant really say, just thoughts thats all,
Phil
EDITTED to say: www.waterinjection.info/phpBB2/ heres a good source of info for water injection and the like, fuel injection before the turbo would probably have been covered in there.

>> Edited by daxtojeiro on Monday 24th October 11:06

sprevett

533 posts

219 months

Saturday 11th February 2006
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I supercharged my TVR 4.5 V8 - amazing results. Selling the engine now so email me if you're serious still. I did 60,000 miles with it so it's just been rebuilt with a new 4.6 block and new big valve low comp heads. email: steve.prevett.ext@fujitsu-siemens.com

Boosted Ls1

21,188 posts

261 months

Saturday 11th February 2006
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I have a roterex supercharger project underway for a 4.8 rv8. Low boost via a blower or turbo's does seem a viable route to power so long as you don't get greedy It'll still cost a few grand though. An eaton 112 is to big for a 4.0 rover, maybe the 90 would be more suitable and cheap!

Boosted.

greenv8s

30,210 posts

285 months

Saturday 11th February 2006
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The M112 is more efficient (for a given flow/pressure) than the M90 though.