My high compression + boost concept

[Rodger]

Not really arguing anything as such, just offering some alternative ideas.

As Sam_Q had said:

".... I am trying to keep as much of the advantages of an atmo setup with the bonus of haveing some more kick in the top end. Basicly as strange as it sounds I am trying to do the equivolent of a hybrid turbo/non turbo setup....."

Begs the eternal question of: "how much more?"

Perhaps go back to the old school N/A route. Keep the high compression and add mild cams. The high compression makes it drivable at low revs as most are agreeing and the mild cams make it draw more air up high. Add some tune and a bit more ignition advance and Sam_Q may find what he is after.

Regards

Rodger

[trd3sg]

Sam - mate im on a very similar path to you as we speak - im in the process of turboing my gen3 3sge which has a 10.5:1 compression ratio from factory - im currently running a microtech on it in n.a form anyway, so will be hoping for 11-12psi on 98 ron and 250 fwhp hopefully on stock internals

the key like most have said is tuning - given that higher cr will mean a bigger bang and higher pressures through the exhaust stroke earlier on in the range than compared with a lower static cr motor, it means you will definitely need a much more efficient turbo.

i know of someone who made 220 fwhp with a totally stock internalled silvertop 20v with a td04 turbo (innefficient), a very weak log manifold and a weak ass plenum which looked like a tim tam's packet - all with a microtech and (wait for it) 15psi of boost !!

a well thought out setup, with good tuning, enough fuel and adequate cooling (both intake temp cooling and motor cooling) will be pretty safe on today's fuel and standards.

id say make sure you have good injectors, an uprated fuel pump, fuel pressure regulator, good ring compression (ie compression test it before you turbo it to make sure your rings arent worn and therefore arent letting oil seep pass them and into the combustion chamber during the power stroke, which will effectively reduce your fuel's octane rating and increase the risk of detonation), a good aftermarket ecu with a reputable tuner, a functionable fan setup, oil cooling of some sort, and all the right tabs on things (boost gauge, oil pressure gauge, oil temp gauge etc)

goodluck with it mate - ill let you know how mine goes in a couple of weeks

[Mr Ed]

Water/meth injection setup to switch on with boost might be a good idea

[bunkyt18]

There should be no power lost due to exhaust restrictions with a NA turbo conversion. NA turbo conversions would be able to give a decent result in terms of power upgrades that would probably be more efficient than the alternative SC. Still, at the end of the day you would not want to run more than 6 to 7 psi with a high comp motor unless you want to tune the motor to within an inch of it's life and risk shortening engine life drastically. There are standard things that require upgrading such as more fuel flow, larger injectors, aftermarket ECU, good intercooler, water/meths injection blah blah. If money is not a problem then turbo would be the way to go. If you want to be practical and cut costs where you can then a super charger setup would be the other alternative. Makes sense to use a SC that suits this kind of motor when there are ones already available that are not very expensive .

Julian Edgard from autospeed has done a lot of research around NA turbo conversions if any body is interested.

[JustenGT8]

I wouldnt sell ANY forced induction as an economiser

Sorry but i don't agree, if the FI is improving VE then the engine becomes more efficient and therefore produces more hp for less effort. Even on 0 psi boost the turbo is improving the airflow to the engine. At worst you at least get the same consumption as n/a but in my experience fuel consumption drops as you are working everything alot less.

My prob with Sam-Q idea is the premise of n/a having any advantage over FI is flawed. If you hi-comp turbo an engine ALL the n/a attributes you might want to keep will still be there PLUS the benefits FI introduces.

As for hp losses to drive a turbo?....effectively none in a well designed system. Ballpark 60% of the combustion process is wasted as heat out the exhaust. The turbo is effectively driven off this waste heat. By mid rpm the turbo only takes approx 30% of this heat energy to be driven so there is nearly always an excess of energy in the system. In addition, in a well designed setup boost pressure exceeds exhaust manifold pressure (usually only by a small amount admittedly) so there are no pumping pressure losses.

Low rpm (and i mean very low as my turbos produce boost from 1100rpm) is obviously where a turbo suffers most but in a hi-comp ratio setup it just performs like an n/a, you wouldn't even know the turbo was there. Exhaust gas flow requirements are low so the turbo presents little restriction and this can be enhanced further with vac actuated wastegates as per most externals gates.

As long as the engine has the attributes to handle FI there are no down sides. Like i said, just turbo and enjoy. People really need to get up to date and stop relying on the old turbo myths...they no longer apply

[Shifty]

Crap idea.

[NeoNasty]

GT8 - TT1UZ GrpA GT4
388rwkw @ 17psi with wheelspin
11.7@122mph
1:09.4 Wakefield Park

what would you know Justen.

PS. I just got a copy of Zoom with your Celica in it. WOW, you sure did a LOT of work on it. I was real impressed.

[JustenGT8]

LOL thanx Neo

[The Witzl]

Hi-comp + Boost = fast.

Heck, i took an old smallport 4age i bought out of a bin for $100, and turbo'ed it.
I then ran a lazy 14.1@ 94mph 1/4 mile.... with a 1.9sec 60ft
Not bad from an otherwise STOCK worn out engine, with less than efficient parts used in the turbo conversion.

That engine was so abused that one of the main bearing caps was almost COMPLETELY undone when i was doing the front main seal.... i just tightened it back up, and put the engine back in the car.

[trd3sg]

Hi-comp + Boost = fast.

Heck, i took an old smallport 4age i bought out of a bin for $100, and turbo'ed it.
I then ran a lazy 14.1@ 94mph 1/4 mile.... with a 1.9sec 60ft
Not bad from an otherwise STOCK worn out engine, with less than efficient parts used in the turbo conversion.

That engine was so abused that one of the main bearing caps was almost COMPLETELY undone when i was doing the front main seal.... i just tightened it back up, and put the engine back in the car.

ahahaha - i can imagine

but yeah justen is on the money here - cant wait for mine

all the haters who claim it wouldve been easier\better to use a 3sgte from scratch will have bite their words soon hopefully - off boost performance and turbo pound - hopefully 250 fwhp - should make for a fun 13 sec street daily driver

[bunkyt18]

"Hi-comp + Boost = fast.

Heck, i took an old smallport 4age i bought out of a bin for $100, and turbo'ed it.
I then ran a lazy 14.1@ 94mph 1/4 mile.... with a 1.9sec 60ft
Not bad from an otherwise STOCK worn out engine, with less than efficient parts used in the turbo conversion." Witz

Yup I have been thinking of doing this kind of thing with my 1GGEU in the Celica XX. Interesting... very interesting ....

[Sam_Q]

thanks to everyone for the possitive replys, I was going to go ahead regardless but this makes me a hell of a lot less wary.

JustenGT8: Could you tell me more about this engine setup that you ran 17psi with? or do you have a link for it? It sounds like a real achievement

I will be running 10% Ethanol 98 RON fuel (E10) which apprently resists detonation quite well and also works very well with forced induction, probably due to its latent cooling.

I do understand what you mean with the VE increasing which helps economy and how it happens even when theres no boost. I believe it but thats only in theory and quite possibly wrong in my case due to something else, as you have also said it's mostly down to my right foot. I love to zoom up hills sometimes and I try not to anymore. I believe that if I go up a hill and i start to hit boost I will be too tempted to floor it, and for the next hill, and the next... and lose all my economy. So it's a psychological thing for me. I really would like to see some figures of peoples economy changes with turbos, I saw Julian Egars Prius results which where increadable.


Rodger: Just as mic said while this does initually sound like a good idea it has some electrical and mechanical limitations that stop it being practical. I dont want to change the topic much so I will only go into it breifly. I saw a person a while back try putting a leaf blower into the intake of his car while on a dyno, it gave a bit of a boost and had a 3kw engine by memory. Now 3000W means that at 12V it would be 250amps. This means it would put a massive load on the battery and be able to run for seconds. I have seen a working system but it had a bank of high discharge batteries in the boot, massive cables, it could only be run for 20 seconds before the heatsoak and battery load would be too much, gave only 5 psi and if that wasnt enough it cost heaps. Your cold air induction has some merit but the effects would be relatively small.

As for the idea of just hotting up my current engine to get a 150% power increase (roughly what i plan on getting) I will need to spend about 10+K rebuild it every 2000km and it would be undriveable on the street. Using a more mild example to get a decent amoutn more power I would need bigger duration and lift cams. This automaticly would throw my driveability and fuel economy out the window. I was going to initually go with this idea though to optimise everything as much as possible without changing the cams.


mic: yes I agree with you, people have always tried to get a turbo to do as much of the rev range as possible. While I on the other hand want to have an engine that runs well without it and doesnt need it down low.


Viper: I never really thought about how having a larger exhaust would effect things off boost, I might purposefully make it 2.5inch all the way, would that be too restrictive?


trd3sg: sounds like a good plan, have you considered mapping it for an ethanol enhanced fuel?

this friend you know, how long he he been running this setup. I will have carefull mapping and I might be doing something very unusual by using a nissan air flow meter.

1J injectors seem to be the go, 380cc and are physically compatable (non VVTi)

I am still building this engine and I can say that it will be in as new condition.

please keep me updated on your progress.



sir2jza70: my plan exactly, I want to wind up the boost till it lightly pings, wind it back a little and then run water/meth injection ontop of that. I was planning on using a hobbs switch at maybe 4psi or something.


shifty: saying its crap and not saying why is just wasting peoples time with your post. If you have something to contribute I will pay attention no matter how negative it is, but posting no information helps no-one.


witzl: thats just awesome, how long have you been running it?

[JustenGT8]

Come up to the dyno day mate and you'll see it in action It's my TT 1UZ, been running high comp turbo for going on 3 years now...heaps of track time and street abuse plus a trip to WSID and no end of road testing. I mostly run at 13psi as 400rwkw is just stupid on the street and the 320rwkw 13psi gives is 'just' manageable

Not much to tell as engine is basically stock with bolt on turbos and upgraded fuel system to cope. I run water injection as additional insurance but doesn't need it at 13psi...haven't tried a 17psi run without it but will do once the new motor is built and i can risk testing the 'stocky' to find the limit.

The key is good ECU/tune, good fuel and inlet temp control.

Just size your turbo correctly please...what you are suggesting will seriously be crap to drive and i can guarantee you'll be unhappy and frustrated with the result. You are basically trying to achieve the undesireable traits of turbos of old...the exact things that gave them the bad name in the 1st place

[Sam_Q]

hmm, I thought you were talking about a 20v, I thought it sounded too good to be true. I know of how tough 1UZs are, either way sounds like a nice package.

I will try real hard to keep heat under check, I will have many heat shields and wraps.

Do you think using an evo turbo like what I plan is a bad match?

[JustenGT8]

20v will never like alot of boost....Jase is the man to talk to about this but basically the 5 valves leave so little head material that spot heating and the head material going soft is apparently a real issue.

If i were to turbo a 20v, and i came very very close to going this way with my KE10, i would run one of the KKR turbos......can't beat them for price and quality is excellent from all reports.

If you run a good enough ECU (Autronic is my choice) then you can map boost against throttle position, or gear or rpm etc etc so you can tune exactly how you want the boost to come on. This will allow you to get a MUCH better result than trying to engineer a late booster by turbo choice. It also allows you to change as you like should you decide you want the car to behave differently.

I have no experience with any of the EVO turbos but it would be a guess by anyone as to how it would run unless they have used one. You are dealing with OEM and in my experience a more generic aftermarket is gonna be alot easier to work with in terms of fittings, pipework, wastegate etc etc. Between Garret and KKR you will find a turbo spot on for a 20v.