1.5... upper limits & weak spots?

[addautomotive]

Ok, we have a couple threads going about 1.5 performance. This intersests me; for motorsports fans, the 1.5 diesel fals into "H" classification 1.5 & lower. Lots of fun potential there.

Question, if one used a 1.6td block with 1.5 rotating components (pistons, conrods & crank), what do you think the "upper limit" of development would be?

Reason I ask: I've read in a couple threads that the 1.5 has cast pistons & crank. I'm wondering how much that caps upper revs & HP.

[Kudagra]

Reason I ask: I've read in a couple threads that the 1.5 has cast pistons & crank. I'm wondering how much that caps upper revs & HP.

The only pistons you can get for the VW IDI diesel are cast. I looked for forged but I was told by custom pistons makers that they dont do diesel.

I would try to destroke a 1.6 to make a 1.5.

[addautomotive]

The only pistons you can get for the VW IDI diesel are cast. I looked for forged but I was told by custom pistons makers that they dont do diesel.

I would try to destroke a 1.6 to make a 1.5.

My thought is to do exactly that. I have a 1.6 TD block, bored 0.50 over. Although, I bet 0.50 over 1.5 pistons are hen's teeth.

I wonder about the crank though.

[Kudagra]

My thought is to do exactly that. I have a 1.6 TD block, bored 0.50 over. Although, I bet 0.50 over 1.5 pistons are hen's teeth.

I wonder about the crank though.

Ive seen them on Ebay more then 1.6 pistons is seems. Also check The Samba.

Here is what I would do If I was going to race this car.

I would have the block re-sleeved. Its stronger and its back to stock size.

When I was going to do this with my 1.6, going price (in the US) was about $50 a hole. Or $200 for the mathmatically challenged.

[jtanguay]

whats the scoop on sleeving though??? how well does that stuff stand up??? any info on the heat transfer? or lack thereof?  :lol:

very interesting...  yes 1.5's are in a class of their own.  wasn't there 1.5's that were making 1000 hp? toyota supra? or was it a bigger engine???

[Kudagra]

Im sure its pretty standard. As far as I know its just about the same thickness as stock cylinders. I just wish they were wet cylinders so they could always be stock size. Just pop out the old cylinders with a puller and slide in new ones.

To my any HP numbers on a supra are useless. They are usually dyno queens. (Lots of HP...no torque)

[addautomotive]

For Project X, I really think ~110-120 HP would have me setup nicely.

I just wonder if the 1.5 crank is weaker than the 1.6 crank... when I did a search some of the threads insinuated that. The advantage would be the short stroke, and the possibility of a free-revving little diesel, with maybe 15-20 PSI of boost in short spurts.

I have access to a few blocks, so I'd just as soon use a stock block than get into sleeving. I was thinking of the 0.50 over block, just because of the marginal displacement bump. 1mm oversize would put it at 1509cc, just over the allowable threshold.

[DVST8R]

No one seems to rember the real issue with the 1.5 was the Head gasket! I belive this was partly to do wtih the small head bolts 11mm vs 12mm on the 1.6. I don't know what the rules, are but if you can upgrade the bolts or studs, I would look at going right to 13mm, if not 12mm forsure and possibly o-rings. The other issue was blow by as the valve cover isn't baffled or somthing of the like?? Maybe someone else can chime in here.

Really I don't think you would brake a crank, even at 30psi.

This build like all builds comes down to how much money you want to spend.

If you are going to rebuild the entire motor anyway, this is what I would do for a moderate budget (if the rules allowed of course):

-Fully balance motor

-Fully blueprinted

-Knife edge crank

-lighten flywheel to 6lbs

-shot peen rods

- ARP or Raceware main studs and rod bolts, and head studs

- Windage tray oilpan gaskget

- machine pistons for a little more valve clearance (lowers compression some and allows for a bigger cam)

- PP race cam, maybe even custom grind for the added posabilty of valve lift

- super heavy duty valve springs, and good stainless retainers

- Possibly oversized valves if there is room and if you can find appropriate valves, without costing a fortune.

- Head (I don't think that a 1.9 head will work but if if could be made to work a ported 1.9head would be the way to go here) not sure what is nicer the 1.6 head or the 1.5 head, which ever is nicer, ported right to the max of the rules. O - RINGED head and BLOCK!

-Intake manifold, either a PD130/150 that is gasket matched and had the casting marks polsihed out, or a custom one from PP.

-GT20 turbo, or if not enough budget a GT15 from the early TDI's

-Exhaust manifold either a gasket matched ported casting marks removed cast 8v piece or a PP equal lenght pulsed manifold.

-Big downpipe and exhaust 3" is perferable.

-Precision FMIC

-FM Oil cooler from either a saab or a volvo (one has a high end oil cooler factory that would be good for adapting.

-Additional crank case vents, venting to a moroso (or similar) catch can not back into the intake

- Lift pump either an intank, or holley red just outside the tank, with bigger lines feed and retun lines (if you can afford the bling go with some nice areoquip SS braided lines. Bigger pickup in the tank. Move the fuel filter out of the engine bay.

- Fuel cooler

- CAI (cold air intake)

- I would start with good OEM injectors 1.9 dual springs, and then after it was all dialed in look at going to merc's or modded lift stockers.

- (I know I will hear a lot of debate here but,) Giles pump without a doubt.
but not a 10mm, not an 11mm, not a 12mm not even the monster 14mm,
but...


















A stock 9mm, with the 1.9camplate. The same pump Malone ran in his Franken pump motor. My reasoning behind this is: His car made 150whp+ like that, 12mm have been known to seize if you spin it them too fast, this motor will need to rev, and by rev I mean like 6000 - 6500rpm.

I am sure that a 1.5 is capable of 150whp, but to make it live is all in the details.  :wink:

[DVST8R]

One more thing have oil squirters put in.  :wink:

[addautomotive]

DVST8R,

Wow, thanks so much for the help. You've certainly given me a lot to think about.

For this application, the only limitation is the 1500cc displacement. Other than that, the sky's the limit.

I'm thinking about starting with a 1.6TD block. I'd build a "mule" engine that I can run in the samurai, and try different setups and adjustments. Once everything is dialed in, I'd then build the "final product" based on the learnings from the "mule".

Question: For the initial "mule" build, do you thinks a copper HG would be sufficient for 20psi?

As for the 9mm pump; I think that makes A LOT of sense. By the figgerin' I've done so far, it'd need to sustain 5500-6000 rpms for as long as 45 seconds. I'd be worried about seizing a larger pump.... keep in mind I'd also be running vegetable oil.