Turbocharging a V8, advice

[fatjon]

Just setting to work on turbocharging an AJP V8 and could use some advice from anyone who has done a V engine before. Simple question, 1 big turbo or a pair of small ones. Way I see it is that small ones spool faster but if you hit a big one with twice as much exhaust flow it should spool pretty quick, cost less and the pipework is a hell of a lot easier. Have retrofitted a lot of 4 pot engines with turbochargers but this is our first V engine project. Advice from anyone with experience would be very welcome.

FatJon

[Slinky]

Are you suggesting that the pipework for a big single is easier than a pair of smaller units?

Where are you thinking of mounting the big single if you go down that route?

BTW, is this staying in a Cerbera or going into something else?

[trackcar]

I've thought about doing this many times but never found anyone to take me up on the work .. good luck I would go single turbo for all the reasons you suggest : simplicity and ease of install. I will be watching this build with great interest, it should be storming! I'm building the AJP8s for our T350 race car for next season .. if it comes in a bit underpowered for class A a turbo conversion might be just the ticket

[stevieturbo]

In reality, opt for whichever is easier packaged, as spool/power differences will be minimal.

[fatjon]

I have a cerbera but this engine is not going in it. We are building a proper thunder saloon from a Vauxhall Omega. The turbo(s) will be in front of the engine as I am keeping in mind that once the system is up and working we may want to try and graft it into the Cerbera or at least have paterns for the manifolds to then do the Cerb. I think if the turbo is kept high, roughly at the height of where the aircon pump is mounted (but forward) it should go in the Cerb with minimal mods. Heat control would be the challenge in the TVR body rather than the mechanics of fitting it all in.

If trackcar=jules in Chesterfield see you on the 12th!

Jon

[fatjon]

I'm leaning heavily towards the single turbo option, anyone want to convince me otherwise? The more I think about lambda measurement, wastegates and boost control the more the twin option looks like a real PITA.

Jon

[Boosted LS1]

I had a call about a racing project like this a couple of weeks ago, is Derek involved or is that a totally different project? Just curious:

From a racing perspective I'd go with one large turbo if you plan to be on boost most of the time and if it's easier to install.

Edited by Boosted LS1 on Thursday 28th August 22:16

[Deltaf01]

Id go single simply because there are less components to package in there, plus theres more in there to go wrong with a twin setup.
Try and keep it simple would be my overriding concern.

But thats just me.

[350Matt]

trackcar said:

I've thought about doing this many times but never found anyone to take me up on the work .. good luck I would go single turbo for all the reasons you suggest : simplicity and ease of install. I will be watching this build with great interest, it should be storming! I'm building the AJP8s for our T350 race car for next season .. if it comes in a bit underpowered for class A a turbo conversion might be just the ticket

A bit off topic

But AJP8 for next season? Whats up with the wilder lump?

PM if you'd rather not open yet another can of speed six worms

Matt

[fatjon]

Boosted LS1 said:

I had a call about a racing project like this a couple of weeks ago, is Derek involved or is that a totally different project? Just curious:

From a racing perspective I'd go with one large turbo if you plan to be on boost most of the time and if it's easier to install.

Edited by Boosted LS1 on Thursday 28th August 22:16

I don't know anyone by that name so it looks like there is another set of madmen around somewhere! The original plan was to drop the engine in a single seater but lets face it, that's suicidal. The only people I have discussed it with in the TVR circle is a chap at clever trevor who is looking into supplying a custom paddle clutch assembly and flywheel.

Jon

[trackcar]

fatjon said:

Boosted LS1 said:

I had a call about a racing project like this a couple of weeks ago, is Derek involved or is that a totally different project? Just curious:

From a racing perspective I'd go with one large turbo if you plan to be on boost most of the time and if it's easier to install.

Edited by Boosted LS1 on Thursday 28th August 22:16

I don't know anyone by that name so it looks like there is another set of madmen around somewhere! The original plan was to drop the engine in a single seater but lets face it, that's suicidal. The only people I have discussed it with in the TVR circle is a chap at clever trevor who is looking into supplying a custom paddle clutch assembly and flywheel.

Jon

Ah that would be with russell from raceproved, we run their paddle clutch in the T350 racer and it's been very reliable, progressive and good value! Yes it's Joo from chesterfield here, sounds like we could have a good chat about your project, sounds great! You'll have to get here early on the 12th though cos thats the weekend i'm away in glasgow for the farewell tour of the stray cats and they're playing friday night!

[Boosted LS1]

fatjon said:

Boosted LS1 said:

I had a call about a racing project like this a couple of weeks ago, is Derek involved or is that a totally different project? Just curious:

From a racing perspective I'd go with one large turbo if you plan to be on boost most of the time and if it's easier to install.

Edited by Boosted LS1 on Thursday 28th August 22:16

I don't know anyone by that name so it looks like there is another set of madmen around somewhere! .

Jon

Thanks Jon, this get more interesting, the plot thickens .

[fatjon]

I'll be early. I need all the help I can get with this damned MBE. I've put the cerb away for a while and running round in one of the other motors so you can have it as long as you need it, no hurry at all.

Jon

[chuntington101]

any reason you have picked the AJP V8 for forced induction??

as long as the turbo(s) are matched to the engine and power requierments then it shouldn't matter if it twins or single.

sounds like a very intresting porject. cant wait to hear more about it.

Chris.

[fatjon]

chuntington101 said:

any reason you have picked the AJP V8 for forced induction??

as long as the turbo(s) are matched to the engine and power requierments then it shouldn't matter if it twins or single.

sounds like a very intresting porject. cant wait to hear more about it.

Chris.

Several reasons why I picked the AJP.

1 it's never been done before so far as I know.
2 if it can make 95BHP/litre without a turbo it has a head start over some yankee crossplane
3 it weighs about the same as a slightly damp feather
4 it's very compact
5 if I drop the RPM ceiling from 7500 to 6800 and get 750BHP it should be very reliable as it will not be highly stressed on the exhaust stroke and not near its rev limit.

There are also a few good reasons not to use an AJP though, like custom pistons to drop the compression, a custom plenum for a single throttle body, its odd firing angles and the cost of the engine. I'm gambling that I can open up the combustion chambers in the head and rework the crowns to get down to maybe 8.6:1 then run maybe 1.5 bar without custom pistons. Either way if we need pistons it's not disaster. Accralite can do a full set to the original dimensions for £880 so to lower the crown a mm or 2 should not be significantly more expensive.

Jon

[Boosted LS1]

^ But lowering the crown isn't really the best way to do it. It's better to get a set of forgings with extra volume in the crown whilst retaining the compression height.

[bertelli_1]

Send Eliot a message mez.co.uk - he'll give you some sound advice.

[fatjon]

Will have to see what can be done without compromising the crown strength. I may be able to get some meat out of the chambers in the head but if it needs pistons so be it. Got the engine under the bonnet today for a test fit. The car could have been designed for it! Loads of room around it and the engine sits well back. Even the gear lever is just a couple of inches from the original location. Because of the sump being offset to the drivers side with all the ancilliaries together there is loads of room on the nearside for a huge exhaust. The test fit has relieved a couple of worries, like clearing the x member and steering box. All in all fitting it's going to quite easy. Will fabricate all the mounts and then remove the engine for its rebuild and mods. The plenum, fual rail and throttle body assembly will all need to be hand made. I reckon that will be among the more challenging bits of the job. The more I look it the less it seems possible that it would ever go in a Cerbera though, but we shall see! Pics to come later.

Jon

[stevieturbo]

New pistons would be the smart way to do it.

[fatjon]

Having had a look at the credentials mssrs Boosted Ls1 and Stevie Turbo I reckon that I will take their well qualified advice and have a new set of pistons made. I suppose on the scale of the rest of the budget for the project the pistons are not going to be the biggest cost compared with potentially trashing an AJP with a piston failure. I've learned over the years of building silly cars is that everytime you cut a corner it will come back and bite you in the wallet so thanks for the reminder!


Jon