1.9 Supercharged 8v

[BackStreetRacecars 3]

I have been toying with the idea of building a 1.9 supercharged 8v... and have been wondering a few things. I'm after some 2nd opinions on my ideas and maybe some ways round problems I foresee...

 

here we go:

 

Cam choice, I have a new man 495/300 (i think) that I want to use possibly....

 

Compression ratio? treat and n/a? or lower? I have been thinkin about lowering the cr like a turbo engine possibly? Either that or work out the boost I'll get from my chosen charger and crack out boyles gas laws and similar to work out internal pressures etc?? Or find someone thats done one before and copy that??!!

 

Gearbox.... TD 'box from a berlingo (i think) Either that or I will get the engine dyno'd and choose a 'box with suitable ratios to compliment the engine

 

ECU and loom. Was looking at 2.0 turbo ecu's and looms for the job. Only because of the boost etc.... Either that or standalone management, but thats a bit expensive for me at the mo I think.

 

Inlet manifold.... Use the plastic 8v turbo one? was planning on using the head from a 2.0 8v anyway as I have one somewhere!

 

Exhaust manifold... Four branch effort? Whats the story with chargers and exhausts? I have just been treating this as if its n/a pretty much...

 

cant really think of anything else that I'm wondering about it just now but hopefully some good replies should ensue... cheers!!!

[CaptainK 11]

Exhaust manifold... Four branch effort? Whats the story with chargers and exhausts? I have just been treating this as if its n/a pretty much...

There is no story. With a SC you keep a "standard / normal" exhaust as no feeds are need to make boost. The SC is run off a belt to your engine (normally on the anciliaries / alternator belt). So essentially it is a N/A setup, but with the supercharger in the inlet piping being run off said belt, and an intercooler to keep the charge temp down.

 

You'll also need to reduce the CR of the engine as N/A engines normally have much higher CR than "boosted" engines (turbo or supercharged). Keeping the original CR and using a supercharger will result in engine going bang.

[M@tt 77]

i'd disagree with CaptainK's comment regarding CR too some extent i'm afraid

 

If you look at the the GTI6 SC conversions, AllanAllen and Madspikes charger projects they all run standard compression and hold up just fine. Modern injection systems are able to handle the increase in CR.

 

Look at something like Megasquirt if your looking for cheap mappable ECU, thats what i'll probably end up using on my SC engine.

[jas-E 1]

I agree with CaptainK. You need to reduce your compression ratio. You can run with N/A comp ratios, but you will be running retarded spark which would increase your exhaust gas temperatures. And to keep those in check you will need to over fuel.

 

Reduce the compression ratio and advance the spark and you will be better in the long run..

[James_R 3]

Use a DKZ engine it's slightly lower CR and have a cam suited to forced induction.

 

Lok at madspikes built pretty interesting, made me think about it too

[madspikes 41 1 Cars]

I agree what all of whats been said, but it all depends on how much boost you are going run. I'm rebuilding my engine at the moment, (note to self update thread) and looking into lowering the compression slightly, but with standard CR it seemed fine until the £20 engine fell apart. Your need to run a intercooler / charge cooler setup to keep the boost temps under control. Your also need to run bigger injectors to cope with the extra fueling required.

 

I have got thermocouple in the exhaust manifold to keep track of the exhaust temps. This was done as we had no idea how the engine deal with the charger, and the mapable ignition.

 

I cant answer the gearbox question yet, but its something I'm going to play around with once the motor is up and running, but the standard box is ok.

 

All I can say is that it was fantastic to drive, but alot of effort to build. If you want easy power go down the GTi6 / 406 SRi turbo road.

 

Mad.

[madspikes 41 1 Cars]

I agree what all of whats been said, but it all depends on how much boost you are going run. I'm rebuilding my engine at the moment, (note to self update thread) and looking into lowering the compression slightly, but with standard CR it seemed fine until the £20 engine fell apart. Your need to run a intercooler / charge cooler setup to keep the boost temps under control. Your also need to run bigger injectors to cope with the extra fueling required.

 

I have got thermocouple in the exhaust manifold to keep track of the exhaust temps. This was done as we had no idea how the engine deal with the charger, and the mapable ignition.

 

I cant answer the gearbox question yet, but its something I'm going to play around with once the motor is up and running, but the standard box is ok.

 

All I can say is that it was fantastic to drive, but alot of effort to build. If you want easy power go down the GTi6 / 406 SRi turbo road.

 

Mad.

[wracing 19]

Please don’t lower your compression ratio, this weekend ive just ran a 1.9 gti engine @ 9.6:1 compression ratio on 12psi please don’t lower it you lose your tuning potential!!!

 

To prevent detonation you need an efficient intercooler and charger, high resolution fuel and ignition control.

 

Just think on a na engine you raise the compression ratio to increase power (liberally speaking). By adding forced induction is another means to raise the compression ratio, why take a step back by lowering the static compression ratio?

 

To prove my point the new twin charged golf runs 11.6:1 comp ratio admittedly they use direct injection which helps cool the charge air.

 

Also epically with turbos low comp ratio = bag of s*it off boost

[wracing 19]

on the manifold side of things use the alloy one we found it has excellent heat soak properties, once cold it stays cold thus helping to maintain cool charge air!

 

the exhaust manifold needs to flow alot, much more than std, larger primaries are need, under simulation my 1.9 assuming 100% volumetric efficiency cylinder emptying 4branch @ 8000 with a turbo running low boost encountered areas of close to supersonic flow. Not good and very inefficient. If i can find it i will post my results. admittly you will never reach 100% ve.

 

 

ecu there’s only one......mega squirt!!!!

[BackStreetRacecars 3]

right well I have a 2.0 8v head to hand to use,and a 1.9 bottom end here, so I will play about with the figures, has anyone got boost figures for eaton chargers? or any chargers for that matter? At different rpms... was thinkin about the new vws style "normal" compression forced induction engines.... I plan on possibly having a mad max style-gear-nob pull up red switch to power the blower on!!!

[wracing 19]

haha that would be great you should be able to scavenge the clutch off an ac pump out of a relatively new car, im not sure if it will be able to transmit the power though!

 

Don’t thing boost think flow! Eaton 5th gen maps

 

best way to read these things is to print it off big and draw over the top with your engine characteristics, if going with Eaton you want to use the m45 but don’t expect to build a 10000rpm monster these units redline at 14000rmp(2:1 with crank) but as they approach that limit they become massively inefficient! Go turbo much more fun also no belt alignment issues and with modem boost control you can make a turbo almost like a supercharger! kinda

[BackStreetRacecars 3]

That website looks cool.... will be getting book marked... fact!!!! I have fitted an eaton charger from a merc kompressor to a saxo vts that had an electro magnetic clutch on it so i was thinkin about that..... Was just lookin for pressure as I can relate it to boost, But I could still work out flow rate, etc with bernoulli's-type-ness...and work out cylinder temperatures with glorious gas laws.... but I think the charger project may be held back as a deer got a touch spirited this evening and decided it liked the front of my car.... promtly ran out and went for me. Hopefully the damage is only as bad as it looks..... If anyuone misses my wanted add.... please find it!! I neeeeed the car...

[allanallen 528 2 Cars]

haha that would be great you should be able to scavenge the clutch off an ac pump out of a relatively new car, im not sure if it will be able to transmit the power though!

 

Don’t thing boost think flow! Eaton 5th gen maps

 

best way to read these things is to print it off big and draw over the top with your engine characteristics, if going with Eaton you want to use the m45 but don’t expect to build a 10000rpm monster these units redline at 14000rmp(2:1 with crank) but as they approach that limit they become massively inefficient! Go turbo much more fun also no belt alignment issues and with modem boost control you can make a turbo almost like a supercharger! kinda

 

bini boys push the m45 well over 16000rpm with no apparent problems. mine runs in the region of 15500rpm max IIRC and is still seems very efficient at high rpms and shows no serious rise in inlet temps.

[sideways danny 0]

Compression - on a high boost supercharger setup, around 9-9.5:1 is a nice generic starting point. But we've put "low boost" setups on completely standard engines (renault clio 172, honda k20) and made massive gains.

This is running rotrex superchargers which are far more efficient than old positive displacement technology (eaton) giving much lower losses from drive, and less heat production. We've just made 260bhp and 219 lb ft on a clio 172 with a 100k old engine, and recently a honda k20 in an exige made over 320bhp.

 

With regard to management, cutting corners is the worst mistake to make. Stock ECUs just dont have the adaptability or access to be setup "right" We made an extra 60 lb ft, and a great deal more power through the rev range, on a turbo clio that had been running re-flashed stock management, just by fitting Omex 600, and mapping CORRECTLY

[allanallen 528 2 Cars]

This is running rotrex superchargers which are far more efficient than old positive displacement technology (eaton) giving much lower losses from drive, and less heat production.

 

 

eaton superchargers are far from inefficient as people seem to keep suggesting. I dont have a problem with rotrex chargers as they are excellent little units, but cant understand why people keep poo pooing eaton type chargers. yes they heat the air a little and take a bit more driving but you can still get excellent results with them, and bottom end torque is excellent. They're also very cheap to pick up second hand whereas the rotrex isn't. the complete conversion i did on my mi cost less than a grand including an ecu, that wouldn't even buy you a rotrex on its own.

 

allaniloveeatonsallen

[wracing 19]

im not been funny but look at the facts

 

 

You can quite clearly see that the charger becomes inefficient at the higher rpm. Not to mention this shows the map for a 5th gen, most of what you can get hold of cheap is a three or four gen.

 

Also while your spinning those roots massively over speed there coating fall off, where it going to get embedded??!!

 

I mean by extrapolating that chart 16000rpm = 40/35% efficient, thats not bearing loss that’s heat generation.

[wracing 19]

if youve got the money this is what you want, its so good its snapping at the heals of turbo technology

 

[allanallen 528 2 Cars]

if youve got the money this is what you want, its so good its snapping at the heals of turbo technology

 

 

That does look very attractive

 

Ive seen the graphs and they do look wank but in the real world they do work well. going off my setup with a decent intercooler, inlet temps are good (sorry cant remember any figures off hand), it makes a steady 8psi throughout the rev range and it pulls hard right up to the limiter when you'd expect power to tale off.

 

I'm just trying to get accross that they do work, when you do internet searches about eaton type blowers you just get the same stuff about them being inefficent and i'm sure this puts everyone off using them. There are better setups as you've shown but the reality is they still work a treat, and for the diy tuner with no money they're excellent. Its just a bit annoying seeing people put off supercharging there car because folk tell them the chargers they're looking at are useless. they then look into buying a rotrex style one as people recommend and cant afford

 

sorry for ranting

[sideways danny 0]

note how i very carefully said Rotrex chargers are MORE efficient without anything negative about the eaton

[wracing 19]

no i know what your saying.

 

talking of intercoolers at speed get a temp lower that atmospheric most of the time just due to the size of it. i mean relalistically as long as your planning on intercooling them they do work i dont disagree with that and you do get that instant tourque that you dont get with turbos, all pros and cons really. if they where crap mini wouldnt have used them in there mass produced cars.

 

and you can beat that wine!!

[ifcho 0]

I think you should be more concerned about using the 2 litre head over the 1.9 block

[GLPoomobile 958]

and you can beat that wine!!

 

Why is the whine more noticeable in some applications over others? Is it simply to do with the amount of under bonnet sound proofing?

 

I was looking at a lot of eBay vids a few weeks back and some of cars that have had Eaton blowers fitted sound utterly ridiculous. When comparing to vids of Minis (New Mini), you can still hear the whine, but it is a noise that is complementing the engine noise and exhaust noise. But on the other end of the scale, a perfect example is a vid of a Mk3 Golf with an Eaton fitted and the whine is totally unbearable! The guy is driving down the road and it sounds like the noisiest electric Milk Float ever I love a bit of supercharger whine, but couldn't live with something as noisey as that, it would piss me off within 5 minutes of driving.

 

Allan - I'd be really interested to see vids of yours. In fact I commented in Garry's topic about timed runs that it'd be interesting to see how yours compared (acceleration wise) since yours should have a more linear power delivery and might actually be the more tractable power plant.

[wracing 19]

the intake wine isnt really effected by soundproofing in my opinion its the intake baffling if you stick a filter on the end of the chager your bound to get more wine, look at the mini intake tract, maybe you could replicate something like this to achieve the same sound?

[MerlinGTI 3]

has anyone got any pics of an 8v fitted with a supercharger?

 

Cheers

[BackStreetRacecars 3]

I think you should be more concerned about using the 2 litre head over the 1.9 block

 

 

 

why is that then??