Idea for ST engine swaps

[dinoracer]

Just an idea, came to me in a conversation with Mark S. the other day.

At the last meeting one of the hotly discussed proposed changes was allowing engine swaps in ST classes(I'm simplifing here). The main aim of the proposed change seems to be allowing 1.8 engines in 1.6 Miatas without a bump into SP. The concern seems to be that we (COM) don't like to make one-car specific rules. But if you don't make it Miata specific, we open up engine swaps to all kinds of combinations, such as an M3 engine into the lightest possible 3 series car, resulting in a huge HP increase.

If the goal of this proposal is to allow stuff like the above, then I'm for the rule as it stands - engine swap see you in SP or P

If the goal is to simply allow a car owner to replace a broken engine with one that is readily available for a particular chassis, or to use a spare engine he /she has rather than buy another, as long as it drops in with minimal additional work and minimal HP gains I think it could be OK

What about if we set a limit on the horsepower/torque gain that could be gained in an engine swap? Maybe allow 10% either way?

I think this would allow for swaps such as the Miata or the Nissan one we were discussing the other night, but not huge gainers like the BMW one mentioned.

Comments/complaints?

[AndyC]

I think if the engine fits without any modifications, then thats fine. I drive a 93 mr2 turbo. Since the car was not sold in the us after 95, any replacement engine would be at least 10 years old, similar to the miata situation. I much rather drop in a 98 or 99 out of the mr2 turbo sold in Japan. This is the exact same block, drops right in, no new motor mounts or anything. Obviously since they made some improvements, this motor would bump my power from 200 to 265 tho and would break your 10% limit. Any limits on horsepower also make it difficult to police with the use of a dyno.

I think the limit should be "does it drop right in?".. this keeps 05 M3 motors out of old 3 series chassis' but allows for swap within the same chassis code.

[JackFFR1846]

You may want to be very, very careful. Although I'm already in P and can do it, a 1st gen 90hp 12 valve CRX (what.....ST4?) can easily fit a nearly 200hp, 16 valve VTEC engine with very few changes.

Same kind of deal can work with 4 cyl BMW. BMW 320i with an E30 M3 engine?

Once into the domestic stuff.....forget it. How hard is it to swap a 302 ford for a 351 or even a 427 or 514 big block?

[SSNH]

jack, i am pretty sure the rule change would not allow the swaps you are talking about...even with the miata/sentra aspect removed.

it allows swapping engines which were available on that chassis.

...will?

[zip4zat]

um... for subarus that means the STI's 2.5l 4cyl turbo (300hp) could replace the 2.0 in the wrx (227hp). These are both on the same chassis. For that matter you could put the 6 speed tranny in too.

[WillM]

If the goal of this proposal is to allow stuff like the above, then I'm for the rule as it stands - engine swap see you in SP or P.

If the goal is to simply allow a car owner to replace a broken engine with one that is readily available for a particular chassis, or to use a spare engine he /she has rather than buy another, as long as it drops in with minimal additional work and minimal HP gains I think it could be OK.

Tom, thanks for putting some tought into the proposal! I agree with you 100%. The intent of the rule is to allow 'mild' swaps like 1.6 -> 1.8 or even 2.0.

What about if we set a limit on the horsepower/torque gain that could be gained in an engine swap? Maybe allow 10% either way?

I think this would allow for swaps such as the Miata or the Nissan one we were discussing the other night, but not huge gainers like the BMW one mentioned.

How about specifying a certain allowable percentage of increase in displacement? If this would work, than I think it would be easier to police than trying to specify the amount of power the swap could add. Thoughts?

You are right that the proposal should be carefully worded as to avoid huge power increases and an unfair advantage for some cars. I tried to do just that in the original wording of the proposal.

In a nutshell, the proposal would make updating/backdating of engines legal in ST if:

• The 'donor' engine was available in the same make, model, and chassis as the 'receipient' car.
• The engine drops in without modification to the engine, body, chassis, motor mounts, etc.
• The car would now be classed in the higher of either the ST class of the car or the ST class of the donor engine.

The last point is key. I cannot think of any specific examples, but for example, if a the engine of a ST2 car was swapped into a ST3 car, then the car would now be classed as ST2. So with the Subaru example, the WRX with the STi engine would now be classed like a STi.

Does that deal with all the loopholes?[/list]

[jlwhorf]

n a nutshell, the proposal would make updating/backdating of engines legal in ST if:

The 'donor' engine was available in the same make, model, and chassis as the 'receipient' car.

The engine drops in without modification to the engine, body, chassis, motor mounts, etc.

The car would now be classed in the higher of either the ST class of the car or the ST class of the donor engine.

Does that deal with all the loopholes?[/list]

According the qualifications above: It could be argued that replacing a 302 with 429 into a 1971 Mustang or replacing a 350 with 454 into a 1974 Corvette would be a legal. Both donor engines where available in the respective chassis and fit with out modification other than exhaust (which is legal in ST), and new motor mounts should be bolted in witha relacement engine for a track car. Although both cars are virtually extinct as a ST car, but it could be a reasonable example. Also, allowing updating/backdating engines should allow for crate motors. It is just as easy to bolt in a 345 HP 302 into a fox chassis as a 225 HP junk yard 302.

Don't get me wrong, I totally agree with allowing motor swaps in ST. I feel that racers should be able to maintain their cars with out resorting to hunting obsolete engines or expensive rebuilds.

Jonathan
900 PA

[mossaidis]

Don't get me wrong, I totally agree with allowing motor swaps in ST. I feel that racers should be able to maintain their cars with out resorting to hunting obsolete engines or expensive rebuilds.

Jonathan
900 PA

That says it all.

At first, I was skeptical of this proposed rule change, but since my motor blow up I'm reconsidering. I am having a hard time finding the same motor, a D16Z6 from a 92 Civic. The only motor I can get that is reasonably priced is a swapped JDM D16A rated at 5 hp lower than the D16Z6. Not a big deal considering a rebuilt D16Z6 would cost me $3000 to get rebuilt by a shop or at least $1500 if I did it myself.