New Turbo for project GSi

[PrecisionBoost]

Well, I finally pulled the trigger and purchased a few new items for the GSi

The engine is broken in reasonably well so I'm looking for 25PSi of boost

I found myself a very nice Garrett GT3071R with a 0.63 A/R turbine

It's V-band, with T3 housing (so no internal wastegate) and it has the anti-surge machining.




I also purchased a new S14 turbo manifold and an equal length B18 manifold so that I can make a new manifold from scratch.

Lastly I purchased a Synapse 40mm wastegate kit ( new type of wastegate... very interesting design )


Hopefully they will be here in enough time to get it all together and on the road before the snow arrives ( yes... northern Canada does suck sometimes )

[MMamdouh]

can you please give me more details about the anti-surge machining?

MMamdouh

[exist3nce]

can you please give me more details about the anti-surge machining?

MMamdouh

See those holes on the compressor cover? They connect to a slot that is inside the compressor cover opening. With a proper anti surge cover you could technically run without a blow off / recirc valve and not ruin your turbo.

[exist3nce]

I found myself a very nice Garrett GT3071R with a 0.63 A/R turbine

It's V-band, with T3 housing (so no internal wastegate) and it has the anti-surge machining.

Lastly I purchased a Synapse 40mm wastegate kit ( new type of wastegate... very interesting design )

Big thumbs up for the GT3071R Fantastic turbo, and it will sound amazing with that anti surge cover!

I've seen the videos for the synapse bov and wastegate, but don't know anyone actually using them. Let us know how it goes!

[nexia182]

wow GT30 is a powerfull turbo!!!!!!

congratulations

[PrecisionBoost]

Here is the plot of the projected boost points from boost onset to 6500 RPM at various PSi Targets.

The projected boost was based upon another other engines using the GT3071R ( nice screen shot of the guys boost at various RPM really helped )

The onset boost does pass over the regular GT3071R surge line but with the porting that surge line is moved to approximatly where the green line is.




The next one is a comparison from Garrett on the ported vs non-ported surge lines.... the non ported GT45 is very similar to the non ported GT3071R

As such I belive the ported shroud GT3071R will have a very similar change in compressor map lines ( which is how I came up with the green line on the first picture )

[PrecisionBoost]

Even for initial testing at 10psi it still plots very nicely between 70% and 76% efficency all the way.

Even at 30 PSI the plot falls nicely into the 72% to 74% range

I predict spool up to be as follows:

0 PSI up to 2500 RPM
10 PSI by 3600 RPM
15 PSI by 3700 RPM
20 PSI by 3800 RPM
25 PSI by 3900 RPM
30 PSI by 4000 RPM

All you need to do is figure out where the turbo will pass the Pressure ratio of 1 ( basicly when it goes from vacuum to 0psi boost )

Then you calculate the mass airflow at that point and draw a dot.

Then you figure out where the turbo will hit the boost level ( based upon other similar sized engines with same turbo )

Then you calculate the mass airflow at that point and draw a dot

Then you connect a line between the first point and second point.

Then you calculate the mass airflow at maximum RPM and draw a third "end" point

Then you draw a straight line from point 2 to point 3

Here is a simple formula for mass airflow...

Ma = (( MAP ) ( Ve )( rpm /2 )(disp)) / (639.6)(460+ Tm )

Where

Ma = mass air flow ( lbs/min )
MAP = manifold absolute pressure = 14.7psi + boost
Ve = Volumetric efficency ( usually 90% to 97% for DOHC engines )
rpm= RPM point your calculating at
disp = displacement of engine in cubic ft
Tm = manifold temperature in deg F ( average is about 130 deg F )

Tm will change depending on compressor efficency and the amount of boost.

A lower boosted engine with an efficent compressor might only be 110 deg F where as a fire breathing dragon running 30 psi might have a manifold temp of 150 deg F


Displacement for a 2.0L = 122

So....I'm going to use 95% efficency at 6500 RPM because the engine has been ported and polished.

MAF = ( ( 14.7 PSI + 30 PSI )( 0.95 ) ( 6500/2 )( 122 ) ) / ( (639.6)( 460+130 ) )

MAF = (44.7 )(0.95)(3250)(122) / (639.6)(590)

MAF = 44.6 lb/min ( at a pressure of 30psi boost and 6500 RPM )

Pressure ratio = MAF / ambient pressure
Pressure ratio = 44.7 PSI / 14.7 PSI
Pressure ratio = 3.04

So.... for this compressor we plot a pressure ratio of 3.04 against a flow of 44.6l b/min and make a point

[PrecisionBoost]

Well the turbo arrived today.... good news and bad news.

Bad news for me is that the turbo was supposed to be coming out of Vancouver BC so that I didn't have to pay duty on a USA/Canada crossing.

So... unfortunatly the turbo came from California... which meant paying Fed Ex $70.00 extra

But now for the good news.... the turbo came directly from Advanced Tuning Products ( better known as ATP turbo )

So that is really good news that ATP was the orignator of the turbo since they are a really decent company.

At first glance it's definitly going to be a tight fit..... now I have to pick up a few more items such as an intake filter with a 4" inlet

But all is good.... at some point next week I hope to get it ceramic coated.

[PrecisionBoost]

My new stainless manifolds arrived.... the one is a Silvia S14 manifold with an offset and the other is an equal length Honda B16 manifold.

The plan is to remove both flanges, weld on the 2.0L 16V flange onto the Silvia manifold and change it to an external wastegate style.

The B16 is going to be an intake manifold... flanges will come off and I will modify it to work with the design I had in mind.

At $99 for the S14 manifold and $149 for the Honda manifold it was cheaper than me making everything myself.

The flanges are mild steel....but the runners are stainless.... so I will be welding on the SS flanges I got from Garrett a few months back (or is it years now )

[gse_turbo]

VERY COOL! I'm pretty interested in seeing how this turns out, it pretty much the same thing I had thought about for a while. it's good to see someone actually doing it. good luck! ...like you'll need it

Garrett

[PrecisionBoost]

Well, I finally made it into the shop to do a bit of work on the S14 manifold.

Step one:
- remove old flange using bandsaw
- I welded a nice square piece of 2.5" pipe to the other side of the flange and squared it up in both dimesions.
- I could have simply used a hacksaw but I wanted to ensure a nice square cut where all pieces are the same



Here is one of the stainless flanges I bought from Daftart/GSETurbo mounted up to the S14 pipes



As you can see they aren't too far off... the first two are perfect and the other two just have to be moved out a bit.

I have to do a test fitment... but I may end up welding on an extension to the tubes to get the turbo in the perfect spot.

[exist3nce]

Very nice, clean cut too. That flange looks good as well... How much power are you actually aiming for ?

[PrecisionBoost]

Well.... that really depends on the chassis and gearbox..... the engine was built for 650WHP ( warranty given for that much power)

Problem is that 650WHP is useless for a FWD car unless your drag racing and modify the front end to take monster drag slicks.


Keep in mind a 1000 HP twin turbo Supra curb weight is around 3600 lbs

The GSi is around 2200 lbs

As such the power to weight ratio of the GSi is 0.295 Horsepower per pound

The twin turbo supra making 1000hp has 0.278 Horsepower per pound


So.... in theory a 650WHp Astra Mk2 chassis will beat a 1000 WHp Supra twin turbo.

In real life that just isn't so.... there is no way to get that power to the ground with such a light car.


So I really don't know how much power I will end up making.... it depends on how much power the car can put down without twisting into a pretzel.

I still have 30PSi of boost in mind so that should in theory push the car up into the 425WHp range.

Personally I think that will be enough to overpower the car even with drag slicks... and I'd be worried about the F28 and axles at that level of power


Originally I did want something in the 600WHp range but the plan was to run an 11,000 RPM Redline ( C20LET head can do that with the right modifications )

That way I'd manage 600WHP but only be making 300 something lb-ft

Torque is the gearbox killer.... if I made peak power in around 9000RPM to 10,000 RPM that would keep the gearbox alive.


I still have more money than time, but I don't have anyone I could trust ( other than Tom ) to work on the car so it's going to take years for me to be "happy" with the end product.

Unfortunatly it seems he may be moving back to Poland so that will definitly slow down my progress.

[gse_turbo]

I like the progress of the build, did you say you already have the motor built?

[PrecisionBoost]

It's the same GSiTurbo engine that has been running at a conservative 10psi for the last year.

The short block machining/blueprinting/balancing / final assembly was done by Bel Engines... they build massive dragster motors.... they only do race engines and are the best around.

They usually don't touch 4cyl engines but Tom convinced them to do one last 2.0L engine.


The head work was done by Tom and Bel worked with him on assembly and upgraded parts.


I've helped along the way with some of the assembly work, removal of the old engine, installation of the new engine, little bit of help configuring things and troubleshooting things.


Tom sold me his car just as we finished it.... the only thing left was to tune it which I paid for.... and we ended up throwing in a number of parts from my inventory to get the fuel system up to where it needed to be A/F wise.

The only reason the boost hasn't been increased past 10PSI is that the engine was in it's initial break in period.... and the Nubira ECU is still fighting things despite our best efforts to make it happy.

The car is in dire need of suspension work and I need to sort out the power steering ( getting an Astra MK4/5 electro/hydraulic system from the UK )

At this point the throttle response is so touchy that the suspension throws me into wild convulsions when ever I go over a bump.

Basicly the suspension is not dampening the small bumps.... so my whole body (thus foot) moves which results in a slight change in throttle position... which jerks the car forward thowing my body around yet again.

You get use to it.... but the car is savage... very hard to drive.... that is part of the reason Tom got out of it.... he didn't have any more cash to dump into the project.... and it does need a fair bit of work to get her up to where we both want to be.

At this point I'm going to finish the mock up of the manifold and put it together so the car is driveable.... then I will see how it spools up.

By that time were probably going to be seeing snow here ..... yes.... we nearly allways have snow by late October up here.... it's allready getting close to freezing on some nights.

Then over the winter I will be installing the F28.... hopefully some uprated Axles.... and most likely redoin the entire intake system.

I'd like to revert back to allowing the Nubira ECU to run a set of Nubira injectors for situations where I'm not in boost.

Currently the big injectors that are in there right now are causing the car to be very rich at idle... which fouls the plugs quite quickly.

I think I may pull out the Greddy E-manage and drop in a Megasquirt.

Then it will be a hybrid.... the Nubira ECU will still control basic functions when the engine is making less than 0psi of boost.

So the Nubira ECU willl control idle and basic fuel injection at idle and partial throttle

Then the megasquirt will be responsible for ignition timing at all times and it will start pulsing the large injectors when boost comes on.


So under 0psi it will be run on the Nubira and when ever it goes into boost the Megasquirt will kick in.

I could do away with the Nubira ECU but in my opinion it's easier to simply let it control the car when not in boost ( which will help fuel effiency )

Who knows... I allways change my mind.... I might end up going 100% megasquirt.

Then again this engine may end up in my Polar express chassis and use it for dragracing.

I do have a nice C20GET kicking around that would fit quite nicely into the GSi and make it a good autocross car


Too many decisions.