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Discussion Starter #1
Hi Everyone.
Here I find myself again after maxing out the power of my car as it is with Webers wanting more power. I have 3 options
1. Go ahead and finish the turbo install and boost it to 5 to 600 hp.I have all the parts and most of the fab work done.
2. Tear the engine down . Put in super high performance rods, get custom heads made, High comp pistons and new cams. I should be able to gain at least 100 hp and keep NA plus turn 9K. (this will cost me about 30K) 20 k heads, 4 k cams , 2 k rods, etc
3. Put the webers back on, keep it like it is and buy a Gallardo to play with . Put twin turbos on that and make a beast.
I have to be working on something or get very bored on the weekends. What are everyones thoughts. If I buy a Murcie or Aventador, I will not want to modify it and probably get bored with it.
 

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Clearly Option 3, the Jalpa engine is not strong enough, the material is 30+ years old and Aluminium molding was not that good in those times.
 

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Lee,

can the Jalpa frame take that much HP without reinforcement? Laust? :)

If you're bored, come up to Indiana for the holidays and we can play with my Urraco? :D

Regards,

Bryan
'74 P250S S/N 15622
Indianapolis IN USA
 

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Keep the Jalpa what it was intended for and buy something more modern that satisfies the itch. It will be more of a headache to make the Jalpa something it was never meant to be. A turbo Gallardo is in your future, sincerely my crystal ball ;)
 

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Why don’t you buy a Gallardo V10 Motor and 6 speed standard transmission and install that in the Jalpa? I have thought of this for awhile.
 

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I have actually thought about building a replica countach on top of a Gallardo chassis and engine... I’ve wanted a countach but everyone says they aren’t fun to drive and at current prices I would be scared to drive one. But if I found one with a dead engine and transmission it would be tempting to make a frankenborghini I... so I like the idea of a Jalpa with a Gallardo heart. I personally think the Jalpa is a great looking car.
 

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I think I chimed in before, but I think option 3 is the best.

The Jalpa lacks power, has a relatively delicate engine, etc. AND it is a pretty heavy car for what it is. It weighs roughly the same as a Gallardo, but has roughly half of the power.

If you want to go fast, I think the Gallardo is your car. Lots of people have gotten mad power out of the Gallardo and the car seem to handle it really well.

I think you would have to more than double the power output of the Jalpa to get it to go as fast as a stock Gallardo. Double the power of a Gallardo and you can chase down some of the fastest cars in the world.
 

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Discussion Starter #8
Great input everyone. I totally agree with you Raymond on the aluminum quality. Pure porous crap. That has been my biggest concern on adding power.I can put in better rods, pistons, etc but cannot fix the core problem of poor casting quality. Blissindy, I appreciate the generous offer but a little too far for a weekend drive. Gdf you may be truly gifted fortune teller. Ever thought about a career change? I like the idea of a frankenghini but don't think the g motor would fit. It would be a great option for a car with no motor. Problem is length and transmission. Jalpa is traverse. It would probably work good on a countach. I think I will scrap the turbo build and reassemble the old girl.
Does anyone know of any project cars. I would not mind a G needing rebuild. I could put in rods, valves, etc. Lots of fun weekend time and a rocket ship at the end. I would to love to find an old countach in need of restoration. That would keep me occupied for a while but almost impossible to find. The problem is worrying about driving. Parts for those are stupid now. I can buy a G for around 100K put 30 or 40 in it and have a 1500Hp true supercar. Real tempting...……. If anyone knows of late model cars G or Murcie needing engine work but otherwise solid, let me know. If I am going to turbo, I have to open the motor anyway so no need to pay for a low mileage car.
 

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can the Jalpa frame take that much HP without reinforcement? Laust? :)

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Wheel spin is the limiting factor for forces on the frame, so yes the frame can handle the HP increase.

Another thing about turbocharging an engine is, that it will not increase the forces on the connecting rods.
There are two main sources of forces on the con-rods, namely inertia and combustion pressure and since they are in oppsite directions, they can actually cancel each other (for the combustion stroke) at a certain rpm and boost combination.

Extending the redline does put more stress on the con-rod, I believe by the square of the rpm increase ratio.

Btw, the transverse engine configuration in the rear, is a challenge to thermal management.

If I had a Jalpa without an engine, I would seriously consider electrifying it. Here are a couple of references:
All Electric Ferrari 308 GTS Specifications - ElectricGT
https://evwest.com/catalog/

Laust
 

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Wheel spin is the limiting factor for forces on the frame, so yes the frame can handle the HP increase ...
Laust
Thanks Laust!! So no worries about momentary forces before spin on the Bravo's Lee is going to add ;) Good to know :) I'm learning ;)
 

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Discussion Starter #11
Laust thanks for the input. You probably have more experience on a turbo Jalpa than anyone. I had read the same about rod stresses . It is much more strain to increase Rpm than to turbo. (Up to a point) How much boost are you running ? I remember an older post where you twisted an axle or something like that. Any idea what kind of Wheel Hp you are making? I had figured with a 2.0 Pressure ratio and good intercooling that I would be in the 550 Shaft HP range. (About like a stock Gallardo) I am running really wide rear tires that are pretty soft so the forces to break the tires loose are much higher than stock. My clutch will slip now before it breaks the wheels loose unless I am going sideways. I have a 400 ft lb Sachs performance clutch but the pressure plate is stock. It slips during very hard acceleration in higher gears and trying to burn out. Engine will, clutch wont. I don't think heat management will be a problem with my much larger air intakes. One is all oil cooler, one is ram air. If I turbo, the ram air one will be half turbo air and half under hood cooling. Right now I actually get a little boost from the ram air as I go faster. The stock design is very restrictive. I am tempted to put a pressure sensor on the intake to see how much pressure it is making. Lee
 

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Lee,

Sorry for the late response and I can only answer some of your questions.

I am running a max boost of 15 psi.

I have never twisted an axle, but form the first day of purchase have had too much noise from the differential and I think diagnosed it correctly to be a misalignment between crown wheel and pinion. Since there is no adjustment for it, I managed to move the crown wheel closer to the pinion by machining eccentrics on the output bearings. Moving the crown wheel closer to the pinion by .006” cut half the noise (but could probably go for another .006”).

I do not know how much power I am making and am not that curious about it. Going into a “power race competition” will relative quickly end in very expensive broken parts and I am sure, that the acceleration just before that point, still is less than that of a reasonable well designed electric family car (yep, I mean Tesla).

I am running 265/45-16 Kumho Ecsta V710 race tires on 9.5” wide rims, so I too have a good grip (on dry asphalt).

With respect to heat management, the transverse engine configuration does not lend itself to much cooling of the engine compartment and if you add turbos, there are extra exhaust pipes (under pressure) heating up the engine and its components. Just after completing the first iteration of the installation I had the car on Streets of Willow (in June -> +100F) and could only do 2 laps before overheating. I see now that you are going for a N/A configuration, so it may not be a problem.

Laust
 

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Discussion Starter #13
Thanks for the reply. I had been looking at about 15 psi. I am probably going to go NA if I can get enough flow out of the new heads and new cams. If not, I plan to harden the internals and may still turbo. I have everything built already, just need to install.
 
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