Late model downdraft 225 Efi 3 liter stage by stage build up

**RSWORDS** · 07-06-2019, 12:39 PM

Originally Posted by vnemous

Chazy????? Old Charlie??????? OMG

Let's just call it fat thumbs. Lol

**RSWORDS** · 07-06-2019, 12:43 PM

Originally Posted by Chaz

Looks like stage one is stage 1, 2, 3, combined ...

The reason I was adamant about ex-port ht is about final "trapped compression" ratio.
To use round numbers, a 300x has a 1.700 , yours is 1.800
If we were to cut your heads to 61cc like an X has , we would need to run AV gas or it's equivalent "ALL" the time.
Cutting them to 64 - 65cc ( from stock 73cc ) will put you right in the same place that a X is stock, @ your port ht.

Cali .. I disagree with the timing issue. Put a light on a 225/250 and then check a 300x and get back to me.
I wouldn't get the box tuned-up "and" slot the pick-up eye. It would be a, one or the other thing.
I slot the eye ( and use allen bolts as hold downs ) because they need all the help they can get off the bottom, and with stock port timing raising the limiter .. is , well ..

I do agree ... the injectors, harness, fuel rail, bridges and braces don't belong in the plenum ...

I've got some stock rubber baby buggy bumper reed cages and some stripped cages. I'll measure the window opening of both and post the diff ...

Gonna do it in steps. The steps may just happen over a couple weeks. Lol

And stage 4 if needed was inspired buy an old picture of yours I found doing some research and will be reserved for if I cant get the chawk moving fast as I'd like.

It was an old black intake with what looked like brake lines coming out of it.....

**RSWORDS** · 07-19-2019, 07:47 AM

Well.... I got the word that Mrs. @Chaz started cleaning up my heads and may have CC'd one for the starting volume already. I think I've figured out the brains behind the operation.

**big tom** · 07-20-2019, 07:49 AM

I have been following some of these posts as my twin 250 efi's are starting to drop compression. A couple quick q's.
1 what will you have into this build?. As I have twins that's a factor for me.
2 What kind of H.P. gain will be seen.
3 Chaz, What is slotting the pick up eye?. Is this for total advance?.

**Chaz** · 07-20-2019, 01:49 PM

Originally Posted by RSWORDS

Well.... I got the word that Mrs. @Chaz started cleaning up my heads and may have CC'd one for the starting volume already. I think I've figured out the brains behind the operation.

All true ...

Worst part is ... she gotz half the money and ... all the P .. err ... lady parts ..

BigTom Asks :

3 Chaz, What is slotting the pick up eye?. Is this for total advance?.

Tom , as you can see in the picture. The stock eye has a hole on one side and a slot on the other. I slot the side with the hole to match the slot. This way I have a little adjustment in the timing. If you were to put , lets say 2* degree's in it. The motor would idle cleaner and run harder thru the mid range.
But like any tune-up, you arrive there rather than set-it and forget it ..

**big tom** · 07-21-2019, 08:00 AM

Tom , as you can see in the picture. The stock eye has a hole on one side and a slot on the other. I slot the side with the hole to match the slot. This way I have a little adjustment in the timing. If you were to put , lets say 2* degree's in it. The motor would idle cleaner and run harder thru the mid range.
But like any tune-up, you arrive there rather than set-it and forget it ..

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Thank you sir..

**big tom** · 07-21-2019, 08:02 AM

rswords will you be balancing the pistons and rods ?.

**Chaz** · 07-21-2019, 09:42 AM

Originally Posted by big tom

rswords will you be balancing the pistons and rods ?.

It's a low hour rotating assy. so I'm pretty sure it's not coming that far apart.
So naturally, the porting is remaining stock.

To answer one of your other questions about H.P. increase. Without a dyno and a mule motor to flog, it's impossible to say with any accuracy. However, guys that have :
Lightened the flywheel, reed block mods + Carson reeds, *reed plate*, cut heads, moved the pick-up, relieved the exhaust have picked up anywhere from 4 to 9 mph.
Since there is no port work done, the motor will not rev any higher ( stock timing events) but what it will do is get there quicker, pull the same prop with more weight onboard or pull a bigger prop at normal weight to the same rpm.

*reed plate* not all updated to 300x style plate.

**XstreamVking** · 07-21-2019, 09:55 AM

So glad to see some 3.0 mods that don't rely on a "tune". Just good old fashioned ingenuity. I have 3 of these motors stored away to tinker with....Took the 2.5 off the V-King and put the 3.0 back on.....Now, im planning some tweaking...

**RSWORDS** · 07-21-2019, 03:45 PM

Originally Posted by XstreamVking

So glad to see some 3.0 mods that don't rely on a "tune". Just good old fashioned ingenuity. I have 3 of these motors stored away to tinker with....Took the 2.5 off the V-King and put the 3.0 back on.....Now, im planning some tweaking...

I hope it turns out well. Lol

**Chaz** · 07-22-2019, 09:31 AM

Big motors , everything set on snooze .... what could go wrong ....

**RSWORDS** · 07-22-2019, 10:43 AM

Originally Posted by Chaz

Big motors , everything set on snooze .... what could go wrong ....

Oh if it can get f'ed up I can do it. Lol

**cali kid** · 07-23-2019, 02:05 PM

Originally Posted by Chaz

Looks like stage one is stage 1, 2, 3, combined ...

The reason I was adamant about ex-port ht is about final "trapped compression" ratio.
To use round numbers, a 300x has a 1.700 , yours is 1.800
If we were to cut your heads to 61cc like an X has , we would need to run AV gas or it's equivalent "ALL" the time.
Cutting them to 64 - 65cc ( from stock 73cc ) will put you right in the same place that a X is stock, @ your port ht.

Cali .. I disagree with the timing issue. Put a light on a 225/250 and then check a 300x and get back to me.
I wouldn't get the box tuned-up "and" slot the pick-up eye. It would be a, one or the other thing.
I slot the eye ( and use allen bolts as hold downs ) because they need all the help they can get off the bottom, and with stock port timing raising the limiter .. is , well ..

I do agree ... the injectors, harness, fuel rail, bridges and braces don't belong in the plenum ...

I've got some stock rubber baby buggy bumper reed cages and some stripped cages. I'll measure the window opening of both and post the diff ...

Ah, with stock box I see the slot on the pick up is a nice trick for more spark lead with out re-programming. Spark advance = HP. up to a point. Thanks Chaz

**RSWORDS** · 07-31-2019, 08:24 PM

Chaz got some pictures over today while cutting my heads. First he flattened the back side then flipped them and started shaving. I'm sure he can give some mor info on how much removed and what CC they are now.