Roe S/C with 8lbs. of boost

[GONABITE]

Yesterday I stoppped by Seans shop and purchased some bigger injectors for my car in plans of some future head work and possible cam. Sean offered to let me borrow his 8lb pulley from his car(of course I took him up on the offer). I installed the injectors new MSD injector conectors and the smaller pulley in about 2 hours. I took the car out this morning and what a noticable difference, you can immediately notice the extra 3 lbs. of boost. The car is winding thru the rpm range so much faster, the mid range torque is incredibly strong as if it wasn't before. I should have it on my car long enough to go and dyno it this week, and the way the car feels now I may even forget how to get back to Sean's shop. I will post results in a few days.

 

[RedGTS]

Please do update us if you dyno. Remember Sean could only get another 10 rwhp or so with the 8 lb pulley and stock heads (although the torque increase was higher), and he believes the heads cause boost creep without being ported that severely limited the benefit of the smaller pulley. If someone figures out a way to get a proportionate increase with the 8 lb pulley (which would be ~75-85 rwhp) and stock heads & cam that would be awesome. Maybe some kind of charge cooler will do the trick; the centrifugal kits are putting down some really big numbers with stock heads & cam, but they are all intercooled.

 

[GONABITE]

Yes his peak number was only around 10 but the low and mid range is where the numbers picked up. I was looking at a dyno sheet he had posted and at 4000 rpm he picked up 70 ft lbs of tq, and 68 hp. Which of course would be nice to see carried all the way through the rpm range. His peak tourque did however increase by 45 which is pretty nice.

 

[Torquemonster]

Unless the puffer is a small one working hard - I'd be amazed if the heads were stalling at 8psi!!!

I've seen big numbers from boosting very small ports that flow a lot less than V10 heads!

Assuming tune is good on the extra boost - the problem will be no intercooler - cool the intake charge as boost increases and there'll be more than 10hp in it.

The fact you seem to have picked up more than Sean could be the air was cooler when you drove, maybe you have a better tune at 8psi.... could be anumber of things - but although the engine will respond to headwork - heads alone will not cause 3psi to only produce 10hp... IMHO.... and an intercooler will be money better spent at least in priority to head work... because then head work will make a bigger difference.

 

[Joel]

The chargecooler isn't going to be possible on the Roe set up.....think about water injection instead

 

[BigCarrot]

The chargecooler isn't going to be possible on the Roe set up.....think about water injection instead

I think Sean has plans to intercool!

 

[Joel]

I'm interested, didn't think there was enough hood height to fit betweeen SC and manifold and cant see how remote could be fitted

 

[BigCarrot]

I think it goes partially in the valley under the intake. I think I remember something like that.

 

[Torquemonster]

The UK ERL Aquamist water injection system - properly setup will do perfectly well if you can't fit an intercooler.... they also work great with an intercooler....

2 or 3D mapped H2O injection will enable much more timing at full boost... and that = power.

 

[MaxedGTS]

The UK ERL Aquamist water injection system - properly setup will do perfectly well if you can't fit an intercooler.... they also work great with an intercooler....

2 or 3D mapped H2O injection will enable much more timing at full boost... and that = power.

i tried one on my sc car for the heck of it. i yanked it off it caused intermitent problems with the ECU!

Max

 

[RedGTS]

Sean has played around with water injection on his car with the blower, but I don't recall any amazing results. It's possible he had it on with the 5 lb pulley before he had any 8's though.

 

[Torquemonster]

MAXGTS - sorry to hear it gave you problems - I've heard they need a MAP sensor to work right which is only a problem when you haven't got the right one... like anything hi tech - unless you can go to someone who is really up on these things - it can quickly all be thrown into the "too hard" basket - but trust me - when set up right - they do amazingly well when pushing the limits. I was lucky in that I had access to someone who builds works rally cars and they use them for world rallying - so to him it was simple... I just paid him and he dialed it all in for me. We got another 6 degrees timing with it - from 18 total to 24 (at full 18lbs boost) - and that was worth a huge power gain (sorry no figures as we ran it at road racing track not on a dyno - but it picked up 15kph on back straight which is a lot - main thing was it did not detonate ever - whereas on 18 degrees without water - it would if a hot day or bad gas.)

re Sean and no worthwhile results - was it an ERL? If so there could be a number of reasons - location of jets being a key.... adequate flow being another. re Location - some use them downstream, some place them as close to throttle body as possible - all have a different effect. Bottom line is if you need spark retard - the water should eliminate that need on the low boost SC cars use.... if it does not - it's trial and error until you get it right.

Tip - water tends to work best as close to the port as possible - this creates equal atmomised spray per cylinder issues but is the way to go for those with the know how and patience to realise its potential. Water properly atmoised has a great intercooling effect - plus one drop of H2O expands 1500 times its own size when it converts to steam - that's gotta be good when it goes in the right hole at the right time - so I'd run 2 - one on each bank - as close as I could to the ports. A factory race team would measure temps on all cylinders and develop the setup until all cylinders got equal intercooling from the water - then the potential would be very high for higher boost.

People have problems and throw them away - but guys have achieved 15:1 compression on pump gas with these things - it's just a lot of fine tuning and experimentation that's all.

Putting the jet at the air intake is pointless IMHO - but many do that and some get results.... but it's really just an expensive humidifier that far away.... just some thoughts.

 

[Cudaman]

Gonabite.... I heard there was another 8 lb Supercharged Viper running around Jacksonville this weekend! All right I confess it was me..... I looked high and low I could not find another Viper in Jacksonville anywhere....except Saturday afternoon late ..... but it was Sean's parked in his shop .....I guess all that rain kept all the others in. The only thing that I could find that wanted to play was a Porsche..... I gave him a serious spanking...Sorry I missed hooking up with you .
Cudaman

 

[Sean Roe]

Hi Torquemonster,

We didn't see any worthwhile results with water injection at the time due to the reason(s) you mention. We were only running 5 psi boost at the time and were not retarding the timing anyway. Now that we're running more boost and are having to retard timing on street gas, the water injection will go back on the test schedule. However, we'll do it differently this time and use the VEC2 to control it based on boost and RPM.

Gonabite's dyno results will be interesting to see compared to mine. On our engine, there was a substantial HP and TQ increase through most all the RPM range until 4,900 RPM. There, the numbers basically flattened. I "think" we may have found the culprit though. We have new valve springs on order and they'll be in this week. The combination of weak valve springs and positive manifold pressure pushing them down was certainly contributing to the flattening of the curve (possible valve float). This R&D motor has been run over 6,000 RPM with 1.7 rockers on stock valve springs dozens of times and has hundreds of pulls on it. She's getting tired.

Regards,
Sean

 

[GONABITE]

Cudman,

I think I just missed you at the shop I was there getting my parts when you called for a weather report. What other mods are done to your car and are you running a different rear gear? 10.3 nice pass!!! What was your 60' time?

 

[Torquemonster]

Sean - yes those valve springs can be pesky little critters! It would certainly explain what happened - lets hope better springs fix it.

yes, mapping the water using the VE2 should help a lot. The ERL unit can be bought with its own ECU - but achieves the same result. The key to the ERL Aquamists success is that it uses a very efficient magnetic pump that runs well over 100psi - this atomises the water much better than the "window washer motors" that I've seen many use.

Good luck - some of those torque figures your customers are coming up with are very impressive - and to 3600rpm will see off most of the really big centrifugal guys too.... that's great bang for buck - must be fun in the wet!