Help me spec my WBX turbo engine!

[Dan Dryden]

This weekend I will be collecting a 2.1 DJ engine which I plan to turbocharge (efi), and put into my '72 super.

I've gained quite a bit of experience through efi turbocharging my 1776cc type 1 engine, so I'm not completely new to this but appreciate that the WBX is a different beast to the type 1.

I'm quite excited about this new project and have been planning the spec of the engine.

It will be mainly street driven but I intend to try to do as many public circuit track sessions as I can possibly afford.
The goal is to achieve an engine which has a nice long, flat torque delivery from low down the rev range but can also rev to around 7000rpm. Power target is around 300BHP.

Please could you share your thoughts and experiences of my planned spec below?
I would like to plan this build as carefully as possible so that I don't have any "if only I'd done this" moments:

2.1 WBX EFI Turbo:

Stock crank
Stock rods with uprated ARP bolts
Stock pistons (to give standard 10.5:1 compression ratio)
Total seal rings
Type 1 solid lifter conversion
Webcam 86b (112 lobe center)
1:1.4 ratio rockers (Need advice on valve springs please - will stock be enough?)
Stock heads with light porting (polish out casting marks)
EFR 6258 turbo
Water/air chargecooler
External oil cooler

My ears are open to any feedback or suggestions on the above. I'd appreciate whatever insight you guys can give.

[AMBROSIA]

Some of what I have learned from several better versed people:

Stock rods will work but not sure where you will source suitable arp bolts from.
They are strong but heavy and suffer ovaling leading to oil pressure loss and exit case left.
T1 aftermarket rods will work but the required 24mm little end bore leave little meat on some.
JC suggested another option is T1 aftermarket rods matched to custom pistons with 22mm pins.

Biggest problem I had with the heads is the valve length which severely limits your aftermarket options to custom made.
Manley offer this service and had I known I would have gone this route for a set of stainless.
I ended up using TRW units (also make Porsche oem stuff) being probably the best stock quality you can get.
An option is to hog out the seats and drop the chambers to a T1 spec length (Have fun with that one )

Stock springs will bind with the web86b and ratios rockers, so no good.
You are also limited on spring heights due to the inlet ports running so close to the spring seats.
JC's single springs have a good rep and that's what I went with.
They are made in China but to his spec of Japanese metallurgy and to his credit when he received shipment he immediately took one and had it cut up and analyzed to confirm it's quality.
Retainers turned out to be an issue again due to spring bind but a stock set of T1 units actually hit the sweet spot, although you have the option of Berg retainers should you find a set.

I was advised to stay below 500' lift with a stock piston/head combo although I found I had plenty of clearance with the web 86b on a 1.3 ratio.

Not wishing to put you off but coming from T1 aftermarket to WBX aftermarket is a bit of a shock!

Iain.

[buildabiggerboxer]

Hi Dan, just a few reflections for mulling over while you scrub and clean things,,the wasser spring deck is only 1.4", as mentioned, not enough for performance cams and rockers, Going with 1.3 rockers helps this, as they normally measure out at nearer 1.4 anyway, you can cut the spring seats safely 1mm, provided the bump is NOT removed from the inlet port, it can be blended, but its there because its the v\spring base, then use T1 dual springs to reach your 7000 rpm goal, singles can suffer surge unless you run a T1 sized base spring cup, otherwise there is nothing to support the spring radialy, the wasser spring base is bigger than T1, it depends on the inner spring to control harmonics with the proper interference on the outer spring and the valve guide boss, german spring retainers are no good for high revs, but AMC ones are ok but a touch heavy, most T1 aftermarket retainers decrease the installed vs height, but some will be ok but need hunting for.
you can use the stock valves as my turbo 2.1 did, but heavy and need plenty of spring pressure, mine was German all new kit tho,,,, BUT,,,, aged exhausts? the problem is no decent stock 9mm stem exhausts are about, one option is to convert to 8mm v,stems\guides which opens choices up. inlets are not a problem.
i like the smell of Modus engineering for machining, near you i believe, i may give them a try as its spread so thinly around my way now days, tho ive seen Baldyne seem to be going again in orpington, must be no1 son in charge i guess, they had or made tooling for most VW work i threw at them, which hopefully still exists. Just checked on Modus, near Tunbridge wells...
regards John BBB

[Dan Dryden]

Ambrosia and BBB, many thanks for taking the time to reply.

It seems to me that perhaps I should stick to the stock cam and intake valves for simplicity (And reduce my performance expectations). I'll look into the Manley valves as it would be re-assuring to have stainless valves. BBB, your suggestion to switch to 8mm stems is also a good shout.

As far as valve springs go, I've been told that James C at Stateside has some pretty good HD springs that I could look into. I currently run dual springs on my Type 1 motor but if I'm not going to rev to 7000 rpm and perhaps keep it down to 6000rpm, is there still any risk of float?

Fastback says that he uses Type 1 ARP rod bolts on his motors in this thread here: http://www.shoptalkforums.com/viewtopic ... 1&start=30
Has anyone else used them successfully?

So, it looks like sticking with well balanced stock components could be the answer here. I'm not too disappointed in that as it could possibly cost less than my original plan.

[buildabiggerboxer]

Sinking the valves also works very well, especially with the stock sizes, the chamber will need working to suit and will drop the cr depending,,, either cut the stock valve seats 2mm, they are plenty deep enough, even .100" is ok, or replace with narrower seats if going up on valve sizes, T1 seats are suitable, this also increases the valves installed height to workable levels.

[Piledriver]

Berg sells +.100" dual spring retainers.
With the right springs and rocker geometry prevents even having to mod the heads much beyond cup size/cut for duals.

Avoid the clubfoot type rockers, kills guides dead.
I'd run more cam lift and OEM 1.1:1s with 8mm Porsche swivel feet, only come in 8mm, may be bigger aftermarket swivels but quality?.

[fastbus]

Hi Dan,
Porting the heads is a must and dual valve springs, use the MV code pistons to drop the compression if your going to turbo it, standard rods are fine up to 6k rpm, hydrolic followers will be fine but type 1 lifter bore and lifters are worth the extra work involved.
Cam spec in my old engine was a Scat C25 running a Garrett t3 turbo and 8 injector efi it made some good power when boost was wound up. You will have to fab a custon plenum chamber for a single throttle body and a custom exhaust system. The water pump and oil filter on the WBX don't allow you to use the type 1 systems available. Exhaust flanges are angled differently on the the WBX compared to the Type 1.
If you want i track day car a dry sump is a must to help prevent oil surging when hard cornering and it will keep the pressure up on a constant.
If you wind up the boost to around 25psi you will be going over the 250bhp mark.

[Dan Dryden]

I'm already swirling lots of ideas around my head based on the above advice!... to the point where I'm still no clearer!

Thanks for the latest advice Fastbus.
I wonder, the engine you had with the C25 cam, which rockers did you use?

I'm gradually realising the chain effect of using modified parts and want to keep specialist machine work down to the bare minimum.
I think a type 1 lifter conversion is a no brainer, but still undecided about work to the heads. It would be nice to keep this down to a minimum... I can do some mild prting work myself.

It got me wondering about using a stock cam with 1.25:1 ratio rockers. Would it be compatable with dual springs and stock valves or would I get coil bind? If 1.25:1 rockers would give me bind, how would standard ratio 1.1:1 rockers perform? It would be interesting to see the specs of the standard DJ cam. Does anyone have these and able to share them on here?

Looking at the advice from Piledriver to use standard ratio rockers combined with a cam with more lift, I started looking at more cam specs. I'm specifically looking for cams with a decent amount of lift and not too much duration as this is what the general concensous on here seems to agree is preferable for turbo engines.
Already using a TCS10 on my current type 1 turbo engine, I have disregarded this cam immediately as I know it is too mild for what I want to achieve.

The TCS20 looks slightly better:
Lift @ cam: .397"/.392" (.435"/.430" lift @1.1:1 rockers)
Duration: 294/284
Lobe Cnt: 112

The TCS30 offers even better lift, but would it be too radical for a street engine?
Lift @ cam: .419"/.397" (.460"/.435" lift @ 1.1:1 rockers)
Duration: 308/294
Lobe Cnt: 112

How have people gone about fitting dual springs? Could I just use type 1 dual springs or is there modification required to make them fit?

[Piledriver]

One thing that helps greatly is Berg +100" spring retainers.
This will allow you to use std T1 "duals" and have the ~correct installed height.

The TCS cams are a bit violent to the lifter bores, but with the bushings and T1 lifters should work fine.
I'm not sure how 1.25s work with the TCS cams.

I would try to use "stock style" rockers rather than the radiused toe type, you can then run swivel feet and its far easier on the guides.
Won't work with hydraulic lifters, the swivels need a little lash for oiling.

[Dan Dryden]

Thanks Pile.
Yes, the TCS cams are now recommended for use with 1.1:1 rockers now:

http://www.kustom1warehouse.net/Engle_c ... 1-2011.htm

I worry about their harshness on the lifters, but I suppose a good set of toolsteel lifters should be able to cope with the extra abuse.

Great info on the berg retainers. They should make a dual spring conversion nice and simple.

What do you think about opting for a TCS30 cam? Would it be too harsh for the street?
I don't want to lose too much "off boost" torque, but want the engine to breath better than my current one which runs a TCS10 and seems to run out of breath at 5000rpm.

[Piledriver]

Its still a ~240 degree cam (@.050") on 112LC.
If you are running out of breath @5K, it's likely more to do with the heads or weak valve springs, rather than the cam.

[Dan Dryden]

Are these the retainers?

http://www.geneberg.com/product_info.ph ... cts_id=284

[Dan Dryden]

Its still a ~240 degree cam (@.050") on 112LC.
If you are running out of breath @5K, it's likely more to do with the heads or weak valve springs, rather than the cam.

1776cc
Heads are CB 044 Magnums (40mm x 35.5mm), running dual valve springs.
Static comp is 7.5:1.