super charging a 2.0 8v tall block

Hi Bill, good work so far!!!

you will probably find that the leap in boost is because the 8v engine breathing falls off above 5000rpm so what you are actually measuring is simply an increase in gauge pressure due to the breathing restriction.

 

5-6psi sounds right to me on that size engine. Its about flow though. Compressor supply vs engine demand. Backing up what Tim says most 8v's on std cams tend to stop breathing past 5-5.5 K. But your compressor would still be suppying lots of air! You can gear it harder to increase the charger supply air. However the low speed tip-ins would be very harsh unless you have some other trick way of bypassing the supplied air.

 

yea I think its flow related for sure.. I added a tapping point pre-throttle body to see what the charger was actually producing.. and it was 10-15psi at just 2-3krpms with the recirc valve disabled.. blip the throttle and it went off gauge (20psi) so plenty of pressure, but as you say, flow + pressure is where it drops back to 5psi (gauge off manifold) when running.

Not a hint of det, stock compression, 1.8t ibiza injectors, 3bar fpr (std)

Its been a balancing act of setting the right preload on the Dv007p I am using for recirc, as it was blowing open on transition between vacuum to boost. running the DV reversed to how I run them on 1.8t also aided the early "leak" it showed. Its not how I want it yet, as to stop the leaking, I have had to use a strong spring, + preload shim, but it does'nt recirc on idle now, which is charger working harder than it needs to. Its venting fine from higher rpms between changes, but I need to find a smarter way of switching the DV signal to open vs hold shut. (maybe employ one of the 1.8t vacuum stores and a switching solenoid.. switched off a pressure switch or throttle somehow.
for now its running surprisingly well given its an experiment... MAF disconnected and idle is fine.. MAF connected and it can idle fine for ages then drop into a cycle hunting badly then stall.
Its not wow power, more according to george (whose car it is) and 1st gear lights up now where it did'nt used to apparently.

all good fun.

What I am surprised by is the other 8v e45 mk3 golf I have seen is running dropped compression, 440cc injectors! and is only making 160-170bhp - OTT fueling to me big time, and lower CR for less response also.. 270cc ibiza injectors support this power peace of cake, 440's is 350bhp region and completely ott for the E45 charger.

 

I take it you have access to ECU control parameters?
On one project like this, tranients were controlled more progressively by adding two dump valves and the PCM was accessed to perform a few tricks to the cal. Other option would be to use normally an open ETB and construct a PWM output circuit to route the charger air progessively to the engine as load increased. Sort of simulating a G40/60 mechanical bypass.
Too many factors to fairly state if the engine with dropped CR works better that the one without. 440cc squirters (Bosch light green things?) would only over fuel if PCM cal is not optimised with slighty worse atomisation at idle loads. Sounds like that owner may have thought bigger was safer/better. 286cc jobs from Ibiza cheap and easy to get I would suppose. Saab 36lb/hr would have been the best compromise though.

 

What it seems to me is its seen as "I have to drop CR" to turbo/supercharge where in effect its dependant on what powerr goals, boost levels are expected as well as ability to fuel and ignite it. I would stick with as high a static CR I could to have the best throttle response and pick up, without having to rely on forced induction alone to produce the power/torque.

440cc injectors installed onto a 170bhp car is cr4p choice of injector size, no matter if you have control of them or not.. and idle controls will be as coarse as you can imagine on them.

and can you stick to plain engish for your anacroyms? PWM I understand.. ETB and PCM escape me tho sorry.. What are you trying to describe here?

"that owner" referred to is one you know from E38 thread I saw you post on. boxman fella.

DTA ecu is likely to be employed to control it unless you know of some handy Simos tuning access tools I can play with.

cheers

 

ETB = Electronic Throttle Body
PCM = Power Control Module
Do not know the boxman chap personally.

 

It is only necessary lower CR in any engine if you are having a serious problem with detonation whereby you end up having to dial in so much retard that your combustion happens extremely late reducing efficiency and your exhaust temps go through the roof meaning that you need to over-fuel for England to keep the temps down.

In this case, the act of lowering the CR therefore gives you an increase in efficiency due to the ability to run a more advanced spark which should outweigh the decrease in efficiency you get through lowering the CR or the decrease in efficiency with the high CR and massive Retard.

As in your case detonation is not a problem then like you say stick with the high CR as the engine will be running most efficiently, feel better to drive all round, and give the best fuel economy.

You could even raise it a bit…….

 

thanks for the explanation..

my bad.. you do know chrisdaman and his eaton 16v ibiza tho? also on thread on E38

was browsing E38 lookign at what other folks had been doing with E45's and came across mention thats all.

 

New Badgerwagen engine build will feature a higher CR turbo motor, to see how much off boost engine response I can recover vs the GT35 blowing thru it.

Seems to me so far the AGG motor on the 5psi boost the E45 produces does'nt need much adjustment at all, as stock spark advance and just larger injectors thus far allow it to run remarkably well. MAF disconencted tho, which dulls the engines response to "blipping" the throttle a lot tho.. and the recirc of the DV as mentioned on idle may have something to do with things

interesting little project none the less. cant be all about throttle bodies and big turbo 1.8t's can it.

 

13:1 CR and 105 RON fuel you will be fine

 

Whining Roots, I would know him

 

Jimmy@ Monster had a 9A Turbo on STD compression. The trick was he had the pistons thermal coated. That car did work very well on the mild 15psi he ran and his very beloved SDS PCM.
5psi from the charger when the engine is on cam is fairly mild boost. Would be interesting to see what will happen if you had a play with the engine control parameters.

 

dta becons to me... when the owner can afford one.

 

This is a brilliant thread as i am currently in the process of building up a lump myself... i have spoken to nando and have come up with the best layout for running this setup on my car which is this..



im hoping to use an evo ricirc.. i was wondering... how far can you take the standard injectors before they are maxing their duty cycle and before i go stacking hg's i might throw it on and see how i get on...

 

good luck with that throttle position. you realise from throttle all the way towards engine will be under vacuum... and any flexi's unless reinforced will collapse.
the DV will achieve what when under vacuum?


ask me how I know

 

the dv is a recirc, so why will it collapse.. surely it will just keep the air in place until i open the throttle again.. so you enter vacuum when you close the throttle and the air thats in the inlet pipes just gets rerouted around the circuit until the throttle opens again..

 

A few months ago, n7ndo and myself went through the above design after benchmarking many OEM applications such as the Mini, Toyota Levin AE92 4AGZE, and W203 180 to 230K.
From experience your application would benefit from lower induction noise and improved tranisent response to maximum torque.

 

Thank god for that i was starting to worry...

nando said there are 3 real options...

the usual.. air filter.. eaton.. fmic.. tb...

then theres the air filter eaton fmic.. g60 tb...

or finally the air filter.. tb... eaton.. fmic.. inlet..


i was just wondering.. as nando said that the g60 tb is the easiest option as it has the bleed on it.. whether there is any other brand/make model etc.. thats out there that a conversion plate could be made up to mount the tb.. which would save all the fuss arsing about..

just a thought???

 

Hi mate, you could cut off the tb end of a mk2 8V and weld it on to your mk3 one. We weld kr lowers to 20vt manifold so can't see why not.

Nando

 

I think im just going to do what you said in your pm about the pipework mate...

charger will be in the post sat cheers again