Charlie Robinson's '99 Riv

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Does Bill get new pistons and stuff or how's that all working?

Bill uses a fresh set of pistons with his build service. He uses OEM unless you provide an aftermarket set, in which case you would receive a credit toward your build fee.

If you go high comp bottom end with all the other stuff you're doing, then you'll have one of the gnarlier Rivs around for sure!

Sir Psycho Sexy wrote:

If you go high comp bottom end with all the other stuff you're doing, then you'll have one of the gnarlier Rivs around for sure!

Higher Compression = bigger pulley than normal, or race gas unless you Intercool. It's really just a trade off. I'm not sure which would actually be better, but if you up the compression, your down-the-road mods are pricey(er). That make sense?

Abaddon wrote:

Sir Psycho Sexy wrote:

If you go high comp bottom end with all the other stuff you're doing, then you'll have one of the gnarlier Rivs around for sure!

Higher Compression = bigger pulley than normal, or race gas unless you Intercool. It's really just a trade off. I'm not sure which would actually be better, but if you up the compression, your down-the-road mods are pricey(er). That make sense?

Definitely. I just thought that the m90 actually performed better running a larger pulley, so the higher compression with a larger pulley worked better than stock compression and trying to spin the blower crazy fast with a smaller pulley. I guess it is effectively the same thing, just more efficient with the highcomp. Am I in the ballpark at all? Haha

You got it. Compression doesn't affect the blower, only the engine and the engine isn't what's always being maxed out. If you can grab 10-20 more hp without taxing the m90 more, do it

I would imagine the N/A bottom would give the car a nice feel when out of boost with the higher compression?

I will talk to Bill about it to see what he can do. From what I've read theres not a whole lot of people for or against the swap.

Anyways, I ordered the cam and misc parts. Heading up to Bill's place as soon as the parts arrive.

I will do my best to take pics and keep yall updated. The ADHD makes the follow up process a struggle.

Ordered cam and goodies on the 23rd, they arrived today via 3-5day UPS. NICE!

Got the trailer and friend with truck ready for Sunday drive to Bill's place up by Detroit.

It's game time, boyz.

..oh wow!  

Nice! That's going to be a mean engine. If you do the high compression build, find someone who knows how to tune it. We've had a couple Rivs with these builds - one went "boom".

I think you're correct the low rpm will be torquier with high-comp, like a smaller pulley would do. I don't see much point since there's already enough torque that traction's an issue, but everyone has a different preference. At least the cam will bump HP in the upper band to balance things out. Good luck!

AA wrote:

We've had a couple Rivs with these builds - one went "boom".

Travis? Dat buster's a hack!

Thanks, homies.
I think I am going to stick with full L67 for now. I cant find a whole lot on the net saying one thing or another about it the bottom/top swap (whichever way you wanna look at it). If i had a separate engine, a car to run it in, and a garage to do the thing, i would consider it, but this is my DD and my goal is to reach a relatively reliable ~330-350whp

I am looking forward to start focusing on the body and interior 'soon'. I was really happy with my stereo setup I was working on and it sucks the engine failed the DAY after I got the stereo wired up and tested.    The good thing is that if the engine didnt fail, who knows how much longer I would have put off these engines upgrades. So there's that..

I know alot of you guys that are still going hard started in 2007 or earlier with your Rivs. I started in 2011 and I am in it for the long run. Looking forward to new paint,  body work, wheels, and a modernized interior. I love this fuggin car and wouldnt trade it for anything else if i could  

350 whp.....nice Charlie.

Goal is around 300 with xp and Gen v. Ultimate goal is 350 but that will happen when it happens.
Towing fat aggie up right now with my friends 2013 raptor. Mechanic bill says she should be good as new and more powerful than ever by this time next week.

yaaaay!

350 +HP engines are bad on fuel, so around 300 is alright.

stan wrote:

350 +HP engines are bad on fuel, so around 300 is alright.

350+hp 3800?

MPH>MPG

Ohh yeah,you guys remember how ewolfe moded his Riv pushing 350+ HP.....but it was  bad on gas.

For MPG, It's not how much HP you make, but how you make it (and how often). I believe the best way to keep stock MPG is to keep stock injectors, stock cam, and stock trans. I've seen mid 30s cruising MPG with mods in sig. I don't think an extra 50 HP (IC, pulley, tune) would impact MPG much at all.

Of course, I'm talking crank and you're talking wheel. Point is, 300 or 350, it won't matter. Damage to economy is already done with the cam install.

AA wrote:

stock injectors

You can actually upgrade to better injectors and not lose any economy as long as they're tuned properly.

With a cam, you kinda have to take a hit on city mpg no matter what. There's no tricks to counter that in tuning. There's more air/fuel just skipping right around the combustion cycle into the exhaust (promoting positive exhaust flow). I've found that my highway is still great though. I assume the higher VE you get from a cam as you increase load and rpm helps the highway mpg especially if it's tuned with the right timing, transmission settings, etc. And with the car being aerodynamic, it just does better and better with more speed.

Injectors are funny sometimes. If the dynamic of spraying and atomization were taken out of the equation, the injector would not affect mpg unless you were running a large enough injector to be hitting minimum pulse width meaning the computer wants less fuel but the injector is already delivering the minimum possible. I haven't encountered that as far as I know even running 80lb injectors with gas. If running stock fuel rails and say 42lb injectors that aren't junk, I wouldn't expect any change in mpg at all.

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You can actually upgrade to better injectors and not lose any economy as long as they're tuned properly.

If by "better" you mean bigger, there's mixed opinion on this. Most tune for proper A/F and flow rate so the PCM delivers correct fueling to run the engine run smoothly at idle/cruise/WOT. But I don't think that necessarily means fuel atomization is optimized like it would be using OEM 33-36 lb injectors with OEM pump. If there were a way to regulate PSI for optimal flow (and atomization) using higher PSI injectors with OEM pump, that would work, but I think most tuners are more concerned with getting proper flow rate to for correct A/F ratio. I don't even know if it's even possible to optimize both with an OEM pump and regulator.

I'm basing my opinion on research, not actual experience with injector swapping. Everything I've read points to lost MPG with larger injectors due to less-optimized atomization. If I saw someone using 60 lb/hr injectors and getting mid 30s MPG, they'd definately have my attention!

AA wrote:

Quote :

You can actually upgrade to better injectors and not lose any economy as long as they're tuned properly.

If by "better" you mean bigger, there's mixed opinion on this. Most tune for proper A/F and flow rate so the PCM delivers correct fueling to run the engine run smoothly at idle/cruise/WOT. But I don't think that necessarily means fuel atomization is optimized like it would be using OEM 33-36 lb injectors with OEM pump. If there were a way to regulate PSI for optimal flow (and atomization) using higher PSI injectors with OEM pump, that would work, but I think most tuners are more concerned with getting proper flow rate to for correct A/F ratio. I don't even know if it's even possible to optimize both with an OEM pump and regulator.

I'm basing my opinion on research, not actual experience with injector swapping. Everything I've read points to lost MPG with larger injectors due to less-optimized atomization. If I saw someone using 60 lb/hr injectors and getting mid 30s MPG, they'd definately have my attention!

I'm just going off of research too, but from what I've read it comes down to 2 simple things. First of which being that if you just upgrade the injectors and nothing else changes you will not gain/lose any MPG or power because the same amount of fuel is still being pushed through them. Since they are bigger you will have a rougher idle because the same amount of gas is being pushed through a bigger area (make sense?). The second thing is something I'm sure you and I can agree on and that is most people upgrade other things as well when they upgrade injectors so they will drive harder and lose some MPG from the mods. The way some people tune them is to just dump fuel into the engine causing a loss in MPG.

I'm not trying to be mean here and if you find something to disprove me please show it. I'm sure somebody on here who has gone to bigger injectors can speak on it and give a good answer.

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Since they are bigger you will have a rougher idle because the same amount of gas is being pushed through a bigger area (make sense?).

The reason for this is larger injectors exhibit worse atomization when using OEM pump pressure. Instead of a fine mist, they dribble (Bernoulli's principle states fluid has lower velocity through a larger diameter).

Atomization is also very important for fuel economy, and is one reason why direct injection achieves such high MPG with high comp ratios, even using forced induction.

There's a relationship between injector, pump, filter, and regulator. They create the optimum pressure for correct atomization. If you change any of these parts, the relationship results in a less optimum pressure.

The PCM controls flow rate by the amount of time it opens each injector, so even though you get the right amount of fuel into the combustion chamber, I wouldn't bet on the atomization part being right.

Thanks, ZZP....................