2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Just got back from MarvelSpeed in TX -- new on car

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Old Oct 4, 2003 | 09:29 PM
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Driv300mph's Avatar
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From: Oklahoma
Just got back from MarvelSpeed in TX -- new on car

Just got back from a long trip to TX and back.. left at 7AM, got back at 8:00PM

List of things they did:
Changed plugs
Fixed vaccum leak
Flushed and filled brake and clutch fluid
Did some brake adjustments
Tuned the Fuel Controller
Replaced fuel filter

What they said: They saw my port, and said that it gave away precious low-end power, but had good high-end power, at the high RPMs. Normal ports are bridged porting, meaning 2 holes and a strip inbetween... mine is just a big hole without that strip.. He said this causes flusteration and doesn't allow for an entry/exit type of thing.

They checked compression, and it seemed to be at 8.4,8.4,7.9 on one, and like 8.2,8.5,8.0 on the other. Brand new engine without porting= compression in the 10s. He said that the reason for the lower compression on the new motor is because of the big port.

He tuned it to the best of his ability, and from what I can tell, I bet it takes about .5 off of the 1/4 mile. Total price was $400.00, which isn't bad considering I was with them from 11:00 to 4:30.

Main thing that interested me... he said that if I put a T04 Turbo on it, which is a good size turbo in the small turbo category, would work VERY well with the port I have. Even said that it would work better with a turbo than a turbo would work with his kind of porting. BUT, that will cost mucho dinero. I'm thinking after extensive looking on the internet, that I might be able to get everything I need for $2000 -- Doubt thats going to happen any time soon, only have $2500 right now, and thats going towards insurance...

I learned that the 2nd gear synchro going out was MY fault... it has to be - It wasn't like that when I got it, and I'm pretty sure it was from that HUGE grind I did... that's MY $600 mistake

So, I'm looking at 3 things-

Having a slow low-end, good top-end car that I could put some flares on (Rims, tires, possibly paint, fix 2nd gear synchros)

Investing on a T04 turbo - FAST car, still decent in the looks department - no money left over, lower MPG

Holding out with what it has now, just fixing the tranny problem, and saving money for insurance, although I'll working at Target for $6.50/hr which is really good for my age I'd say...
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Old Oct 4, 2003 | 09:48 PM
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Glad you decided to go with Don. Hes a great guy and you cant beat almost 30 years experience with rotarys
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Old Oct 4, 2003 | 10:28 PM
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From: n
Re: Just got back from MarvelSpeed in TX -- new on car

Originally posted by Driv300mph
What they said: They saw my port, and said that it gave away precious low-end power, but had good high-end power, at the high RPMs. Normal ports are bridged porting, meaning 2 holes and a strip inbetween... mine is just a big hole without that strip.. He said this causes flusteration and doesn't allow for an entry/exit type of thing.
Got pictures of your ports?



They checked compression, and it seemed to be at 8.4,8.4,7.9 on one, and like 8.2,8.5,8.0 on the other. Brand new engine without porting= compression in the 10s. He said that the reason for the lower compression on the new motor is because of the big port.
This is something I question - porting cannot lower compression readings; it can only raise them.&nbsp Also, there is no way in hell a stock rotor'd engine can make compression number in the 10's - this means it'll be pushing over 140psi of pressure!&nbsp I've heard of engine possibly hitting 130psi, but no ways it's going to crack 140psi.

It really sounds like bullshit to me...


-Ted
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Old Oct 4, 2003 | 10:39 PM
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From: Oklahoma
Yes, check www.cardomain.com/id/driv300mph -- go to the 3rd page...

Oh, and are you calling Don Marvel a liar??? Thats a big nono....
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Old Oct 4, 2003 | 11:45 PM
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Originally posted by Driv300mph
Oh, and are you calling Don Marvel a liar??? Thats a big nono....
I would call god liar if he said the same thing.
If the gauge were in bar, a 10 would be 145psi.
If the gauge were in kg/cm^2, a 10 would be 142psi.
It's bullshit that any motor with 8.5:1, 9.0:1, 9.4:1, or even 9.7:1 compressor ratios would hit pressures that high on a Mazda spec cranking test (under 250RPM).&nbsp This highest numbers I've seen was a bit over 130psi - bridgeport motor with 9.7:1 rotors.

Also, porting does NOT lower the compression test results.&nbsp If anything it'll be higher/better - we're talking increase in VE.&nbsp I'll call him a liar on that too.

Don Marvel isn't a god.&nbsp I've heard some bad things come out of that shop myself.


-Ted
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Old Oct 4, 2003 | 11:48 PM
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From: n
Originally posted by Driv300mph
Yes, check www.cardomain.com/id/driv300mph -- go to the 3rd page...
Is this a U.S.-spec 6-port 13B?&nbsp No sleeves?&nbsp Or the pic is without sleeves?&nbsp It looks like the primary and 6-port passages were almost melded together?&nbsp So they recommended to turbo an NA engine???


-Ted
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Old Oct 5, 2003 | 02:30 PM
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Well, I bought the car from NJ, where all work was done by J.R's Rotary performance (Judge Ito) -- Supposedly, he has made 3 or 4 of these ports. Must be without sleeves, because it has pineapple 6-port racing sleeves. THey melded it? You mean took out the bridge, yeah.

Yeah, they reccomend to put a snail on it... I hope I can find the money to do so... I start work soon, so let's hope!
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Old Oct 5, 2003 | 03:46 PM
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Ah, I was just going to say it was Judge Ito's work.


-Ted
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Old Oct 5, 2003 | 03:56 PM
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haha, yep...

Other porting is faster on an N/A -- thats what Marvel Speed said... BUT, since this will work way better with a turbo, that's my only option for more speed, unless I get a rebuild...
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