1.8 V6 Upgrade

[9000rpm]

Hi everybody. I am from Spain (sorry for my bad English).

I´ve seen there is a big interest in engine swaps from larger displacement engines (V6 2.5 Probe and Mx-6) but I believe that is actually against this car philosophy: the smallest V6 ever built (as far as I know, please tell me if I am wrong).

My way has been totally different, instead of an engine swap, I took the way of developing and upgrading the engine (more costly, indeed).

I´ll tell you what I did:

1.-Heads flowed and rised C.R to 11,8:1. 3 angle valve job and grind.
2.- Camshafts reprofilling (a bit more lift , much more duration). My own cam design.
3.-Adjustable cam gears.. obviously.
4.-4340 Steel rods, custom made, longer than stock... lighter than stock.
5.-Custom built pistons (obviously.. for longer rods). Slipper type. Lighter, 1 mm oversize (about 1945cc)
6.-Crank upgrade, polished, rebalanced, cryogenic treated. Lightened (only about 5%)
7.- Reclocked ECU to 8100 rpm. (69.6mm stroke was claiming for it from the very fist moment!!!)
8.- Additional ECU for engine mapping.
9.- New injectors, more flow and better spray.
10. A lot of small (but important) changes as intake (always keeping the stock airbox, crank pulley, spark plugs...

I´ve thought of stroking the crankshaft, but I was thinking of more revs and wanted to keep average piston speed into reasonable values, but If I knew rpm limit to 8100 , I would!

This engine sounds and revs like heaven. It makes 182 Hp @ 7700 rpm and 23Kgm @5600 (crank). Good enough for me.

Future changes I am fitting a fully programmable Haltech E11V2 system looking for 9000 rpm and... maybe buy another engine for my stroker....

Well, it´s obvious the engine swap is more popular but that only makes me love mine more!.

All the best from SPAIN!

[babyblueMX3]

really nice project you got there !!

[TsiMiata]

Since the physical size and weight of the 2.5 engines are no more than the 1.8 you really havent killed the essence of the car. If the 2.5 was larger and heavier than I would agree. Like putting a V-8 in an RX-7 to me totally kills the spirit of an RX-7.

[9000rpm]

Hi TsiMiata.

Sorry I can´t aggree with you because the essence of the car for me (not the final word for anyone but me)is:

1.- Being the smallest V6 ever built.
2.- Having very short stroke and light internals:
tons of revs and instant response.

This is what I tried to make stand out in my engine.

I am sure that a 2.5 with all this job could rev almost as high and make much more power but that would be even more expensive and would never rev (under same conditions) the same as this engine does.

Best regards.

[Nd4SpdSe]

It used to be the smallest v6 built, i belive BMW made a 1.3l v6 sometime afterwards

[9000rpm]

I had no idea of this engine. But was it a prototype?. I´ve neve heard of a BMW since 90´s with such an engine.

[TsiMiata]

But in stock form the 2.5 revs just as high, if not higher and makes more Hp than your modded 1.8. Do those same mods to the 2.5 and theres no comparison to the 1.8. I personally believe the 1.8 was a giant mistake on mazdas part. The 2.5 makes more power and gets better gas mileage to boot. there is no sacrifice in weight either. If they had sold this car back in the the day with a 2.5 they would have made a killing. It would have been by far the fastest hot hatch of the day.

With my 2.5 the throttle responce is MUCH better than the 1.8. I just stomp the throttle in 1st and the car almost instantly jumps to redline. Torque makes cars responsive. The 1.8 doesn't have any.

[9000rpm]

In Spain, 2,5L engine makes 162 Hp and 22.5Kgm in stock form as well as the 626. I have no idea about power figures for this engine in USA.

You are right, the 2.5 V6 engine revs (european market) to about 7350 and the 1.8 to 7250rpm.

Needless to say the 2.5L have much more potential and I agree is torque what pulls but as you know, 6 300cc cylinders have different feeling than 6 413cc. It´s no only a matter of 1/4 mile times but also sensations from a unique engine . How many 2.5 V6s do you know? and 1,8s?

[mxmaz]

tsi is talking about the 2.5 klze having more hp then yours with 200. Yours is the most powerful n/a k8 i heard of so far. Good job.

<small>[ December 15, 2004, 03:11 PM: Message edited by: mxmaz ]</small>

[lakersfan1]

Originally posted by 9000rpm:

You are right, the 2.5 V6 engine revs (european market) to about 7350 and the 1.8 to 7250rpm.

In the U.S. the 2.5 goes AT LEAST to 7500 RPM, and the K8 goes to 7750 RPM. People have revved the KL to 8,000 RPM and above no probelem before, though.

And a quote from one of the ProbeTalk.com gurus is as follows "A KL will laugh at 9000RPM. It has a 1.86:1 rod ratio and a 74.2mm stroke. It's mean piston speed is going to be MUCH lower than even any stock honda that I know of at 9000RPM. That means less stress, which means more longevity at that RPM. I wouldn't put the absolute limit of a KL at stock bottm end geometry at anything under 12000RPM."

[JWMX3]

N/A K8 with 182hp is quite impressive

[babyblueMX3]

have you tried you k8 on the track yet ?? my friend did an impressive 14.9 with his k8 highly modded but still n/a

[mitmaks]

wow man you did lots of work to that k8, Id say that you couldve gotten like 2 klze's swapped for that probably and have 200hp engine sitting there to begin with instead of 180+hp but good luck on it

[bubbaflaat]

You say you wanted to stay with the 1800cc displacment. But why did you up the displacment then? Now you have essentially a KF? Anything can be made fast for the right price. I really don't understand the motivation. If you wanted to be unique so bad, you could have just bought like a delorean or something. There is alot more K8s in mx-3s than KLs. Because they come with that engine from the factory. Duh! LOL

[9000rpm]

Hi BubbaFlat,

There are also more Ferraris F40 with the stock engine than with Civic 1.4 engine. But that is not enough. I am talking about engines not cars. The V6 1.8 is unique in its class ever and I could tell you at least 10 different 2.5 V6 in Europe!!. I am sorry you don´t understand.

The reason I bored the engine is only because of wear, anyway it doen´t even go to the 2.0L class also not that common