High compression, turbo.

S

Sigma

Member +
Righty, I've come up with a game plan, and wanted to see if anyone had looked into doing this before with a 4/5E - FTE.

The usual route with these engines, as we all know so well, is loosely Forge, Lower compression, big boost. Now, while this can create lots and lots of power, my aim is purely driveablity with the figures sat around 250bhp.

What I want to acheive, is roughly this figure, but instead of a TD04 running at 1.2bar, my challenge is to do it on a hybrid CT9, running no more than 1.0bar!

How, or why, I hear you ask?

What I want, is something that off boost, feels like a strong N/A to drive, pretty much along the lines of a VTEC turbo, but made from the trusty engine we all admire. I also want it to be quite cammy and rev to around 9500-10000rpm with sufficient boost.

My plan is to roughly end up with a forged 1331, ported, polished, skimmed right down and gas flown cylinder head with big valves, crazy lift n/a style cams. I'm going to deck the block as much as possible and run an n/a 0.6mm TRD headgasket.

Downstairs, it'll have a lightened & balanced crankshaft, the lightest weight forged pistons and rods fastened to a lightened flywheel and an exedy clutch to put up with the power.

Should hopefully end up with about 10.5:1 compression ratio, if I can remove about 3mm from the combustion chamber.

I reckon I'll be into it for about £5k when it's running, but hopefully, it might be a concept, worth doing.

Opinions/views/comments are all nessasery ;)

Tommy
 
TurboDave

TurboDave

Member +
If you skim 3mm off the block your going to be nearer 1200cc not 1331.

The problem is if you want to increase the comp ratio so much then you can do it much more safely and easier by just running more boost on the hybrid as with the correct spec hybrid you can create full boost before 3000rpm and this would increase your comp ratio enough.

With forced induction (turbocharged) you dont really need wild cams as air is being forced in under pressure anyway so you dont need to try to force it in with the use of wild cams.

Just my 2p

:)
 
H

Harvey

Member +
I think you will have mods on your back saying wrong section... haha

Anyway, i know where your coming from as this is exactyly what i want, a superbly drivaable 250bhp. However i think the only way for it is a 5E.

There are a few problems i see with your goals... namely... the CT9!

It will not support that BHP.

First off - high revs and cams... High revs + CT9 = no. Its too small, as you must be aware its pointless revving a 4EFTE with CT9, just no need to exceed 6k rpm normally.

Crazy cams - no. There is a fine line on cams, too lairy and they will be detrimental. You do NOT wants lots of overlap like you would NA.

I think running around a 10:1 CR with a CT9 would be asking for trouble, all that heat at 1 bar!

My plan has always been a 5E, probably around 8.5:1CR with a garret GT25R and about 240-250bhp.

I am considering a GT28R though for a bit more go at expense of lag. I think a GT25R would spool extremely well on a nice 5E.
 
S

Sigma

Member +
Hmm, thanks for your input Dave :)

Im going to wait until the thread's complete, print it out and put it into the engines document folder.

And similarly, Harvey. :)
 
TurboDave

TurboDave

Member +
For reference aswell I believe its around every 3.7psi you increase boost by you increase the comp ratio by 1.
 
S

Sigma

Member +
Is that effectively?

So on the 1331, for 3.7psi positive, you ineffect, increase the CR by 1?
 
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Harvey

Member +
Thats interesting info. Would it not depend on the size of turbo though? Ie bigger turbo shifts more air.

For the hybrid route then you might get a nice set up on the 4E running maybe more CR (perhaps forged piston) by skimming the head a little and a TRD 0.6 gasket, maybe getting close to 9:1 and run 1 bar. Apparently the tong CT9 hybrid can see about 210bhp at 1 bar. This is what i may well bedoing in the short term (bar the headgasket and skimming) but need to see the condition of my 4E after i have run a stock CT9 at 1 bar.
 
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Dave@TM-developments.com

Trader
TurboDave said:
If you skim 3mm off the block your going to be nearer 1200cc not 1331.

The problem is if you want to increase the comp ratio so much then you can do it much more safely and easier by just running more boost on the hybrid as with the correct spec hybrid you can create full boost before 3000rpm and this would increase your comp ratio enough.

With forced induction (turbocharged) you dont really need wild cams as air is being forced in under pressure anyway so you dont need to try to force it in with the use of wild cams.

Just my 2p

:)
Click to expand...


3mm off the stroke (not Block) would be 1280cc
 
nexia201

nexia201

Member +
A high comp engine with a turbo feels really nice! Had my aygo engine turboed before putting the 4 efte in (1ltr 12v 3cyl) and that had 10.5 cr and the responce from the engine was just nice 0-60 8secs and quarter mile 15.8 so not that bad for a 1 ltr.

so i guess that a 5e left with high comp and a small turbo like ct9 would still work just dont need to rev over 7,000 rpm as you will be getting loads of power from it that you dont need to be revving 10,000!
 
T

Timmy

Member +
ct9 hybrid will run out of puff at about 8k anyway.
If you want responce stock compression and some sort of gt25 would be the way to go.
Or if you want to be really outrageous 4agze.
 
munday

munday

Member +
I really dont see the point in it TBH, yeah you could do it, but why spend all that money for such little power? If you want something with low down power but still screams to 8-9k you have to be kidding!

You will have to find a compromise, low down power and revving to standard rev limit would be achievable.

Something no-one else has mentioned about the cams...'Crazy high lift cams' will shift the power right up the rev range too.

HTH :drive:
 
S

Sigma

Member +
Hmmm.

Still going to acheive it me thinks.

Hopefully will be buying a complete fucked engine soon to have a play with. ;)

Might take a couple of years to do, but I can assure you this thing will be the way forward when it's done.

250Ft/Ib's // 220bhp!

Torque is the answer kids!
 
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hardcoreep

Member +
I plan to go this route at my next rebuild. Just gonna use a thinner head gasket. I always wonder why people use the harder route than the most simple. Is gonna be a high CR (for a Starlet) CT9 4E.
 
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hoochhenry

Guest
listen do it right from the start get yourself a 1.5 block and boost the f**k out of it save yourself the money and the hassle f**k the civics crap..........big ass turbo ihi one cant go wrong then :drive:
 
TurboDave

TurboDave

Member +
Dave@Starletgtturbo.co.uk said:
3mm off the stroke (not Block) would be 1280cc
Click to expand...

Didnt do the math but, If its -3mm off the block = -3mm (off the stroke respectivly) plus the dished pistons (not sure if you can get high comp dished pistons), anyway it wouldnt be far off 1200cc and you would ideally need the dished pistons at -~12cc each to counteract the det on such a high comp ratio with boost......
 
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