New rally engine advice

[Boost_4_Life]

I bought another starlet for a new wild rally project. It is complete with this if i want it..


I'm currently running a silvertop 20V. Question to you guys since I dont know my older 4A's very well, which engine is a better base for modding? The plan is to stay NA 1600, but try and get more grunt obviously, my 20v is currently standard. Would i get more out of tweaking the 20v, or more out of the 16 valve? I can probably spend around 5k on the motor and machining will be mates rates through family engine builder.

Thoughts people? Btw what are the 16valves above actually worth? It obviously had some quads stuck on, but not finished

[Dell'Orto]

If its a smallport, you can get good power out of them - even stock they have more low end torque than a 20v. Go smallport 16v with big lairy cams and millions of compression

[rollaholic]

no more than 4-500 i would have thought for a good runner.

[matt dunn]

no more than 4-500 i would have thought for a good runner.

a complete smallport is probably worth more than that,

and with the Quads and adapter it definatly is worth way more than that.

[Boost_4_Life]

If its a smallport, you can get good power out of them - even stock they have more low end torque than a 20v.

Well this is what we want i guess, need many torques for rally, not all top end power. That's what has been good about the silvertop, it seemed to have good mid punch. Although the motor is very tired now, 7 years of rallying, been upside down once, sat for 2 years while the car was being rollover repaired, and still going strong. It doesnt even use oil! which is probably why it no longer makes power..

[RomanV]

I reckon use the most powerful factory motor and spend the money on bolt on bits. That way you will go faster because youll beat on it harder, as if you blow it up there is nothing to lose. you only need to buy a new block to get going again. Rather than needing to build another motor.

[ee904age]

Looks to me like its a Bigport, not really an ideal base without a lot of work. Better off with a smallport although they're getting harder to find these days, or as mentioned, a silvertop.

[Mr Revhead]

Silvertop with a link and a good intake and exhaust will be the way to go. If the budget allows maybe some rally cams from kelfords or Franklin's etc.
A decent tune on a silvertop gains a fair bit of power. Plus easier to find and much cheaper than a smallport.

[QikStarlie]

Looks to me like its a Bigport, not really an ideal base without a lot of work. Better off with a smallport although they're getting harder to find these days, or as mentioned, a silvertop.

place money on one in pic being a smallport.

shameless self promotion. smallport with big cams and quads:

http://www.youtube.com/watch?v=e_vH-hNhOw4

after driving a kp starlet with standard smallport the above would pretty much match power by around 4000 and by 5000 would be like night and day all the way up to 9000rpm. so actually had a wider power band than standard.

silvertop would be good for thrash and throw away factor like others said though.

[iOnic]

Smallport ftw

[Truenotch]

+ 1 for smallport. They've always impressed me over 20v's and you'll be able to get mid range punch.

Do what QikStarlie did and you'll have a very quick starlet .

[RedMist]

Smallport is a better high dollar development engine.
Silvertop yields little through tuning. My silvertops were 122 and 123 WHP. Blacktop 126. Supersmallport 178whp (smallport with ports reduced in size, injectors shifted, quads, shim over bucket, and forged internals. )

I did have a cammed, bumped compression 20 valve that developed 146whp.

The problem with 20 valve engines is the centre valve. Which way do you swirl the charge? and how do you bump compression without having a piston that looks like a tripple tittied porn stars implants? Flame propogation across the charge must be next to impossible!! Let alone the detonation points created across it's peaks.

[TRD Man]

There's a lot of money gets wasted on rally car development and most of it in the engine.
Here's the thing - you might develop more power by spending $5K on a smallport, and you might get a little more more torque. It might rev better, sound better and dreaming about your new motor might give you the warm fuzzies. But I'll bet you a pound to a pinch of shit that where it matters, on the timesheets, there'll be very little, if any, improvement.
If I had $4 ~ 5K to spend I'd be looking at gearing, throwing away the liteace diff and installing a T series with LSD, suspension and tyres. Attention to those things will actually reap benefit.

[rollaholic]

no more than 4-500 i would have thought for a good runner.

a complete smallport is probably worth more than that,

and with the Quads and adapter it definatly is worth way more than that.

to be fair i've been outta the 4age game for a few years now, but was picking up complete ones for 5-600.

the quads for sure are worth probably as much as the engine with the adapter n stuff, but thats a different discussion. and like TRD man said, a fairly expensively pointless one

if we are talking the engine in the picture, if you wanted to use all RWD 4age bobbins thats probably worth as much as the basic engine too.

[QikStarlie]

Smallport is a better high dollar development engine.
Silvertop yields little through tuning. My silvertops were 122 and 123 WHP. Blacktop 126. Supersmallport 178whp (smallport with ports reduced in size, injectors shifted, quads, shim over bucket, and forged internals. )

I did have a cammed, bumped compression 20 valve that developed 146whp.

The problem with 20 valve engines is the centre valve. Which way do you swirl the charge? and how do you bump compression without having a piston that looks like a tripple tittied porn stars implants? Flame propogation across the charge must be next to impossible!! Let alone the detonation points created across it's peaks.

mine me asking, what pistons and compression ratio you were running in your smallport? were you running outboard injection or just moved back from the port? sorry bit off topic

[Boost_4_Life]

If I had $4 ~ 5K to spend I'd be looking at gearing, throwing away the liteace diff and installing a T series with LSD, suspension and tyres. Attention to those things will actually reap benefit.

yep fully agree Bruce. Ive actually got a good rx7 lsd in the car now, bilsteins all round, and done work on getting the geometry sorted. I only use dunlops now too, the improvements in handling and stage times are night and day. I'm a huge believer in getting the handling right first esp in gravel rally, which is why the engine has been last on the list!

In saying that, maybe ill just stick with the 20v and basic mods, and throw more money into the gearbox... The close ratio T50 is ... ok... but id really love a sequential The main aim for the new car is more strengthening and a proper 4 link setup etc for the rear done properly.

[shihad]

Silvertop with a link and a good intake and exhaust will be the way to go. If the budget allows maybe some rally cams from kelfords or Franklin's etc.
A decent tune on a silvertop gains a fair bit of power. Plus easier to find and much cheaper than a smallport.

why would you recomend a silvertop over a blacktop.if your gana go through the hassle of 20v why pick a silvertop.a blacktop will go better with said mods.the only advantage i can see is the intial cost of purchasing would be lower but with a bit of time you can find cheap blacktops as well.

[~SlideWays~]

why would you recomend a silvertop over a blacktop.

Guessing conrods?

[KinLoud]

Daniel (BZR4AGE)

Threw a number of TODA parts at his NA blacktop
... from memory
- high comp pistons
- big cams
- adjustable cam wheels (i think)
- Link computer
Head wasn't ported - std factory!

He got something like 132kw at the wheels at some high rpm - yes I know it's a dynopac dyno don't bitch about overread/undereading dynos
It's still impressive for na 4age


I drove it - no torque below 3000rpm started pulling at 4000rpm and was mighty above 6000rpm

Here is his thread - read right through to the bottom to see exactly what cams he ended up with in it's final setup
viewtopic.php?t=67634&highlight=power

Ken

[Dell'Orto]

I drove it - no torque below 3000rpm started pulling at 4000rpm and was mighty above 6000rpm

So standard 20v powerband then?